Oblitérer vs Obliterate

Oblitérer is nearly always used to mean cancel, as in a stamp. Cachet d'oblitération - postmark.
Obliterate means to do away with or to wipe out. It can be translated by effacer - to erase or to wear down or by rayer - to cross out.

Occupé vs Occupied 

Occupé is from occuper - to occupy in all senses of the word. It can also mean to employ or to keep busy: Mon travail m'occupe beaucoup - My work keeps me very busy.
Occupied is the past participle of occupy - occuper, habiter, remplir.

Office vs Office 

Office is a semi-false cognate. In addition to the meanings below, it can refer to duties, church services or prayers, or a pantry.
Office can mean the physical place where one works as well as the office or position that someone holds.

Once vs Once 

Once = ounce.
Once can mean une fois or jadis.

Opportunité vs Opportunity

Opportunité refers to timeliness or appropriateness: Nous discutons de l'opportunité d'aller à la plage - We're discussing the appropriateness of going to the beach (under the circumstances).
Opportunity leans toward favorable circumstances for a particular action or event. It's an opportunity to improve your French - C'est une occasion de te perfectionner en français.

Or vs Or

Or has two completely different meanings. It is the word for gold: or fin - fine gold. It is also a conjunction used to make a transition from one idea to another, meaning now or whereas: J'attendais au pire, or il a attendu patiemment - I expected the worst, whereas he waited patiently.
Or is simply a conjunction used to denote an alternative; the French equivalent is ou : I need to buy a pen or a pencil - Je dois acheter un stylo ou un crayon.

Organe vs Organ

Organe refers to the organs of the body and international organs.
Organ is also the musical instrument orgue.

Ostensible vs Ostensible

Ostensible means obvious or conspicuous: Son indifférence est ostensible - Her indifference is conspicuous.
Ostensible means apparent or supposed: His ostensible reason was to help us - Sa raison prétendu était de nous aider.

Ours vs Ours 

Un ours is a bear.
Ours is the possessive pronoun le nôtre.

Ouverture vs Overture 

Ouverture is a semi-false congate. In addition to overture, it the French word for opening 
Overture means ouverture or avance.

Pain vs Pain

Pain is the French word for bread.
Pain is the English word for douleur, peine, souffrance.

Pair vs Pair

Un pair means a peer; as an adjective, pair means even: le côté pair de la rue - the even-numbers side of the street.
A pair is usually translated by une paire : a pair of shoes - une paire de chausseurs.

Pale vs Pale

Une pale is an oar, paddle, or propeller blade.
Pale means light in color. When referring to a person's complexion, it is translated by pâle. But pale blue - bleu clair.

Parti/Partie vs Party 

Parti can refer to several different things: a political party, an option or course of action (prendre un parti - to make a decision), or a match (as in he's a good match for you). It is also the past participle of partir. Partie can mean a part (e.g., une partie du film - a part of the film), a field or subject, a game (e.g., une partie de cartes - a game of cards), or a party in a trial.
Party can also mean une fête, soirée or réception; un correspondant (au téléphone), or un groupe/une équipe. 

Passer vs Pass

Passer is a semi-false cognate. It is normally translated by to pass, except when talking about a test. Je vais passer un examen cet après-midi - I'm going to take a test this afternoon.
Pass is translated by réussir when talking about a test: I passed the test - J'ai réussi à l'examen.

Patron vs Patron

Patron is an owner, boss, or employer.
Patron is a client, someone who purchases from a store, restaurant, or other business: un client or (for the theater only) un habitué.

Pays vs Pays

Pays refers to a certain territory, usually a country, but can on occasion refer to a village.
Pays is the third person singular conjugation of the verb to pay: he pays me cash - il me paie en liquide.

Personne vs Person

Personne is a semi-false cognate. As a noun, it means person, but as a pronoun, it can mean anyone or no one: Elle le connais mieux que personne - She knows him better than anyone. Personne n'est ici - No one is here.
Person refers to a human being.

Phrase vs Phrase 

Phrase is a sentence.
Phrase refers to une expression or locution.

Physicien vs Physician

Physicien is a physicist, while physician is a médicin.

Pie vs Pie

Pie refers to a magpie.
Pie indicates une tarte or une tourte.

Pièce vs Piece

Pièce is a semi-false cognate. It means piece only in the sense of broken pieces. Otherwise, it indicates a room, sheet of paper, or coin.
Piece is a part of something - un morceau or une tranche.

Pinte vs Pint 

Pinte means a quart (in Québec) and a bar or café (in Switzerland). In standard French, it refers to an archaic unit of measurement.
Pint is approximately un demi-litre.

Police vs Police

Police is a semi-false cognate. In addition to a law-enforcing body, it can also mean policy (e.g., insurance) and font.
Police refers only to the law-enforcing body. There are two different organizations in France: la police - under the Ministry of the Interior and la gendarmerie - under the Ministry of War.

Politique vs Politics 

Politique can be the adjective political or a noun: un politique = politician while une politique = politics or a policy
Politics refers only to la politique.

Pond vs Pond 

Pond is from the verb pondre - to lay (an egg).
Pond is un étang.

Pot vs Pot

Un Pot can be a jar, earthenware pot, can, or carton. There is also a familiar expression " Prendre un pot " - to have a drink.
A Pot is a cooking vessel: une marmite or une casserole. Pot is also a slang term for marijuana - marie-jeanne.

Pour vs Pour

Pour is the French preposition  for.
Pour is a verb which means verser or pleuvoir à verse.

Prétendre vs Pretend

Prétendre means to claim or assert: Il prétend savoir jouer du piano - He claims to be able to play the piano. Prétendu - alleged or supposed.
Pretend means to make believe or to feign: She's pretending to be sick - Elle simule (or elle feint) d'être malade.

Propre vs Proper / Prop 

Propre can mean clean or own (as in ma propre voiture - my own car).
Proper means convenable or adéquat and a Prop is un support or un étai. 

Prune vs Prune 

Prune refers to a plum.
Prune can be a noun - un pruneau or a verb - tailler, élaguer. 

Qualité vs Quality

Qualité is a semi-false cognate. It means both quality (e.g., of a product) and capacity or position: en sa qualité de maire - in his capacity as mayor.
Quality refers to the characteristics of things or people: the quality of life - la qualité de la vie.

Quête vs Quest

Quête is a semi-false cognate. The main sense is a collection, but it can also be used to refer to something like the quest for the holy grail or a pursuit of the absolute.
Quest can also be used for less noble pursuits: quest for a job - à la recherche d'un emploi.

Quille vs Quill

Quille refers to a skittle, one of the pins used in the British game of ninepins, as well as to the game itself. Quille also means keel, as in the keel of a boat.
Quill is the shaft of a feather tuyau de plume, a large wing or tail feather penne, and the sharp spine found on porcupines piquant.

Quitter vs Quit

Quitter is a semi-false cognate: it means both to leave and to quit (ie, leave something for good).
Quit nearly always means to leave something for good.

Raide vs Raid 

Raide is the French adjective for stiff, taut, or steep.
Raid is the English noun for un raid or une incursion.

Raisin vs Raisin

Raisin is the French word for grape.
Raisin is un raisin sec.

Rampant vs Rampant

Rampant is the French adjective for creeping or crawling: Le chat rampant m'a dérangé - The creeping cat disturbed me.
Rampant means growing without limit: Rampant vegetation covers the wall - La végétation exubérante couvre le mur.

Rang vs Rang

Rang is a row, line, or rank. In Canadian French, it can be a country road.
Rang is the past participle of ring - sonner.

Râpe/Râper vs Rape 

Râpe is a grater or grinder. Râper means to grate, rasp, or grind.
Rape is the noun viol or the verb violer.

Rater vs Rate 

Rater means to misfire, miss, mess up, or fail.
Rate is the noun proportion or taux or the verb évaluer or considérer. 

Récipient vs Recipient 

Récipient is a container or receptacle.
Recipient refers to la personne qui reçoit, la déstinataire, or le bénéficiaire.

Refus vs Refuse

Refus means refusal or insubordination
Refuse (as a noun) refers to garbage: détritus, ordures, déchets. The verb Refuse is equivalent to refuser in French.

Regard vs Regard 

Regard can mean a glance, expression (on one's face), manhole, or peephole.
Regard can mean attention, considération, respect, or estime.

Rein vs Rein 

Rein is a kidney.
Rein is une rêne or une guide. 

Remarquer vs Remark 

Remarquer is a semi-false cognate. It can mean to notice or to remark. Une remarque is a comment or remark.
Remark is both the noun and the verb - remarque(r).

Replacer vs Replace 

Replacer means to put something back in its place: to re-place it.
Replace means remplacer or remettre.

Reporter vs Report 

Reporter means to postpone or to take back.
Report as a verb means rapporter, déclarer, or dénoncer. The noun refers to un rapport or une rumeur.

Représentation vs Representation

Représentation is a semi-false cognate. In addition to the English meanings of the word, it can also refer to theatrical performances.
Representation refers to a notation or a graphic, as well as representation in government.

Responsable vs Responsible

Responsable is a semi-false cognate. In addition to an adjective, Responsable is a noun meaning responsible party, official, representative, or person in charge.
Responsible is equivalent to its French cognate.

Rester vs Rest

Rester is a semi-false cognate. It usually means to stay or remain: Je suis restée à la maison - I stayed at the house. When it is used idiomatically, it is translated by rest: He refused to let the matter rest - Il refusait d'en rester là.
The verb Rest in the sense of getting some rest is translated by se reposer: Elle ne se repose jamais - She never rests.

Résumer vs Resume

Résumer means to summarize.
Resume means to begin again: reprendre, recommencer.

Revenu vs Revenue 

Revenu is the equivalent of revenue or income, but it is also the past participle of revenir - to come back.
Revenue means revenu or rentes.

Revue vs Revue

Revue is a semi-false cognate. In addtion to revue, it often means a magazine as well as review or inspection.
Revue is a revue or spectacle.

Route vs Route 

Route is a semi-false cognate. It can refer to a maritime or trade route or else to a road.
Route means itinéraire, voie, or parcours.