(a.) Not common; unusual; infrequent; rare\; hence, remarkable; strange; as, an uncommon season; an uncommon degree of cold or heat; uncommon courage.

almost unheard-of appalling astonishing at a premium breakaway conspicuous different egregious exceptional extraordinary extremely fabulous fantastic few formidable in short supply incredible infrequent marked marvelous notable noteworthy noticeable novel occasional of mark offbeat original out of print out of season out of stock outstanding rare rarely recherche remarkable scanty scarce seldom seldom met with seldom seen signal singular slow sparse sporadic strange striking sui generis superior uncommonly uncustomary undreamed-of unexpected unfamiliar unfrequent unheard-of unimaginable unique unordinary unthinkable unthought-of unusual unusually unwonted wonderful