sui generis

being the one or ones of a class with no other members <among history's greats Leonardo da Vinci is often considered sui generis—a man of such stupendous genius that the world may never see his like again> Synonyms alone, lone, one, one-off, singular, sole, solitary, special, only, uniqueRelated Words single, solo, unaccompanied, unattended; incomparable, inimitable, matchless, peerless, unequaled (or unequalled), unmatched, unparalleled, unrivaled (or unrivalled), unsurpassable, unsurpassed; distinct, distinctive, individual, separate; nonceNear Antonyms divers, manifold, multifarious, myriad; assorted, heterogenous, miscellaneous, mixed, motley, patchwork, promiscuous, varied; popular, prevailing, prevalent, rampant; perennial, recurrent, repeated