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

ace, one, unity, I

WordNet sense 2 (the single one of its kind):

singular, unique

WordNet sense 3 (being the only one; single and isolated from others):

only, sole, solitary

WordNet sense 4 (characteristic of or meant for a single person or thing):

individual, separate, separate

WordNet sense 5 (not shared):

unshared

WordNet sense 6 (always the same; showing a single form or character in all occurrences):

uniform, unvarying

WordNet sense 7 (not married or related to the unmarried state):

unmarried

WordNet sense 8 (not divided among or brought to bear on more than one object or objective):

exclusive, undivided

WordNet sense 9 (gathered together or made less diffuse):

concentrated

WordNet sense 10 (a base hit on which the batter stops safely at first base):

bingle