WordNet sense 1 (somewhat ill or prone to illness):

ailing, peaked, poorly, seedy, sickly, unwell, peaked, under the weather

WordNet sense 2 (affected by an impairment of normal physical or mental function):

ill, sick

WordNet sense 3 ((usually followed by `to') strongly opposed):

antipathetic, averse, loath, loth, antipathetical

WordNet sense 4 (unwilling because of mild dislike or disapproval):

disinclined