Englishundesirable
adjective
1 a mix of medicines may result in undesirable side effects:
unpleasant, disagreeable, nasty, unacceptable, unwelcome, unwanted, unwished-for, unenviable, unappealing;
unfortunate, infelicitous.
▷antonyms desirable, pleasant, preferable.
2 William had been involved with some very undesirable people:
unpleasant, disagreeable, distasteful, displeasing, unacceptable, off-putting, obnoxious;
nasty, disgusting, awful, terrible, dreadful, frightful, repulsive, repellent, repugnant, revolting, abhorrent, loathsome, hateful, detestable, reprehensible, deplorable, appalling, insufferable, intolerable, despicable, contemptible, beyond the pale, odious, vile, obscene, foul, unsavory, unpalatable, sickening, nauseating, nauseous, noxious;
informal ghastly, horrible, horrid;
British, informal beastly;
archaic disgustful, loathly;
rare exceptionable, rebarbative.
▷antonyms pleasant, agreeable, acceptable.