UNIQUE, existing as the only one of its kind; very unusual [adj]
ing without a like or equal unequaled could stare at the flames, each one new, violent, unique Robert Coover
usual a very unique ball-point pen we were fairly unique, the sixty of us, in that there wasn't one good mixer in the bunch J. D. Salinger
being the only one sole his unique concern was his own comfort I can't walk away with a unique copy. Suppose I lost it? Kingsley Amis the unique factorization of a number into prime factors