Quorum : Assemblage, Gathering

Radiant : radiant,beamy,efflugent,reflugent

Rakish : Dapper,dashing , devil-may-care,jaunty,natty,pert,raffish,snappy,spiffy,spruce

Rambunctious : boisterous,Robustious,rumbustious,unruly 

Rapacious : edacious,esurient,predatory,raptorial,ravial,ravenous,voracious,vulturirien

vulturous,wolfish

Rapport : resonance

Raze : dismantle,level, pull down, rase, take down, tear down

Reactioanry : extreme right winger, far rightm reactionist , ultraconservative

Recapitulate : recap, repeat, reprise 

Reciprocal  : Multiplicative inverse, mutual , reciprocal cross 

Reclamation : Reformation, rehabilitation, renewal 

Reclusive : Cloistered, recluse, secluded , sequestered ,withdrawn 

Reconnoitre : Recce, scout

Rectify : amend,correct, reclaim, refine, reform, regenrate, remediate, remedy, repair, 

right

Red herring : preliminary prospectus, smoked herring 

Redolent : aromatic, evocative, remindful, reminiscent , resonant , smelling 

Regatta : meet, sports meeting 

Regime : authorities,government, regimen 

Regnanat : Reigning , ruling 

relegate  : banish, bar, break , bump, classify, demote, kick downstairs, pass on, submit 

Relief : alleviation, assuagement, backup, backup man, ease, easement, fill-in, ministration, moderation, reliever, relievo, respite, rest, rest period , rilievo, sculptural relief, stand in, subsititute, succour 

Remedial : alterative,curative, sanative, sanatory, theraputic

Renege : go back on , renege on, renegue, renegue on ,revoke

Renovate : animate, freshen up ,quicken , reaniamte, recreate, refurbish 

repair, restitute, revivify, vivify 

Repute : esteem, look pon, look upon, regard as, reputation , take to be 

think of 

Resonance : plangency , rapport, reverberance, ringing, sonority, sonorousness, vibrancy

Resound : echo, make noise, reverberate , ring 

Restitution : amends, damages ,indemnification , indemnity, redress, redressal, regaining, resotration , return 

Retrench : conserve, husband, economize, economise

 Riff :flick, flip, thumb, riffle, leaf, riff