WordNet sense 1 (the smallest whole number or a numeral representing this number):

ace, single, unity, I

WordNet sense 2 (having the indivisible character of a unit):

unitary

WordNet sense 3 (characterized by unity; being or joined into a single entity):

united

WordNet sense 4 (used of a single unit or thing; not two or more):

ane

WordNet sense 5 (being or denoting a numerical quantity but not order):

cardinal

WordNet sense 6 (beyond what is ordinary or usual; highly unusual or exceptional or remarkable):

extraordinary

WordNet sense 7 (made or joined or united into one):

combined

WordNet sense 8 (vague or not clearly defined or stated):

indefinite

WordNet sense 9 (eminent beyond or above comparison):

matchless, nonpareil, peerless, unmatched, unrivaled, unrivalled, unmatchable

WordNet sense 10 (such that comparison is impossible; unsuitable for comparison or lacking features that can be compared):

incomparable, uncomparable