WordNet sense 1 (not pleasing in odor or taste):

unsavory, unsavoury

WordNet sense 2 (not pleasant or acceptable to the taste or mind):

unpalatable

WordNet sense 3 (highly offensive; arousing aversion or disgust):

disgusting, foul, loathsome, repellent, revolting, wicked, yucky, disgustful, loathly, repellant, repelling, skanky, wicked

WordNet sense 4 (unpleasant or disgusting especially to the senses):

offensive