Requirement, requisite, prerequisite can all mean something that is regarded as necessary to the success or perfection of a thing.
Repugnant vs Repellent vs Abhorrent vs Distasteful vs Obnoxious vs Invidious
Repugnant, repellent, abhorrent, distasteful, obnoxious, invidious are comparable when they mean so alien or unlikable as to arouse antagonism and aversion.
Reprove vs Rebuke vs Reprimand vs Admonish vs Reproach vs Chide
Reprove, rebuke, reprimand, admonish, reproach, chide can all mean to criticize adversely, especially in order to warn of or to correct a fault.
Reproduction vs Duplicate vs Copy vs Carbon copy vs Facsimile vs Replica vs Transcript
Reproduction, duplicate, copy, carbon copy, facsimile, replica, transcript are comparable when they mean one thing which closely or essentially resembles something that has already been made, produced, or written.
Represent vs Depict vs Portray vs Delineate vs Picture vs Limn
Represent, depict, portray, delineate, picture, limn can mean to present an image or lifelike imitation of (as in art).
Report vs Rumor vs Gossip vs Hearsay
Report, rumor, gossip, hearsay are comparable when they mean common talk or an instance of it that spreads rapidly.
Replace vs Displace vs Supplant vs Supersede
Replace, displace, supplant, supersede are rarely interchangeable terms, but they can carry the same basic meaning—to put a person or thing out of his or its place or into the place of another.
Repeat vs Iterate vs Reiterate vs Ingeminate
Repeat, iterate, reiterate, ingeminate can all mean to say again.
Reparation vs Redress vs Amends vs Restitution vs Indemnity
Reparation, redress, amends, restitution, indemnity are comparable when they mean a return for something lost or suffered, usually through the fault of another.
Renunciation vs Abnegation vs Self-abnegation vs Self-denial
Renunciation, abnegation, self-abnegation, self-denial can all mean voluntary surrender or putting aside of something desired or desirable.
Renew vs Restore vs Refresh vs Renovate vs Refurbish vs Rejuvenate
Renew, restore, refresh, renovate, refurbish, rejuvenate are comparable when they mean to give a person or thing that has become old, worn, or exhausted the qualities or appearance of what is fresh or new or young.
Renegade vs Apostate vs Turncoat vs Recreant vs Backslider
Renegade, apostate, turncoat, recreant, backslider are strongly derogatory terms denoting a person who forsakes his faith or party, a cause, or an allegiance, and aligns himself with another.