Answer: unique

AnswerCrossword Clue
UNIQUEMatchless.
uniquemost unusual or rare
uniquesomething that is rare or the only one of its kind / existing as the only one of its kind
uniqueonly
UNIQUEUnmatched
UNIQUEMore than unusual
UNIQUERarer than rare
UNIQUEWithout equal
UNIQUENotable.
UNIQUEOne and only.
UNIQUEUnparalleled
UNIQUESui generis
UNIQUEIncomparable
UNIQUEOne of a kind
UNIQUEBeyond rare
UNIQUESingular
UNIQUEPeerless
UNIQUEOne-of-a-kind
UNIQUEMatchless