rack, v. [stretch], [strain], torture, agonize; [harass], [persecute], [torment].
rack and ruin. (Colloq.) [destruction], [ruin].
racket, n. [din], [uproar], [clamor], babel, clangor, blare, [noise], [hullabaloo], hilarity, vociferation; (Slang) carouse, [revel], [dissipation].
racy, a. fine-flavored, [pungent], [rich]; [spirited], [piquant], fresh and [lively]. Antonyms: insipid, [vapid], [tasteless], [flavorless], [dull], prosaic.
radiance, n. effulgence, refulgence, [brilliancy], [brightness].
radiant, a. effulgent, refulgent, [brilliant]. See bright.
radiate, v. [shine], [beam], [gleam]; diverge.
radiated, a. [divergent].
radiation, n. irradiance, irradiation; [divergence]. Antonym: convergence.
radical, a. [original], [fundamental]; [extreme], thorough-going; [primitive]. Antonyms: conservative, [moderate], [slight], [trifling], derivative.