WordNet sense 1 (of the remaining member of a pair, of socks e.g.):

unmatched, unpaired, unmated

WordNet sense 2 (either not matched or unsuitably matched):

mismatched

WordNet sense 3 (beyond or deviating from the usual or expected):

curious, funny, peculiar, rum, rummy, singular

WordNet sense 4 (being definitely out of the ordinary and unexpected; slightly odd or even a bit weird):

strange, unusual

WordNet sense 5 (not used up):

left, leftover, remaining, unexpended

WordNet sense 6 (not used up completely):

unexhausted

WordNet sense 7 (not exact):

inexact