(of a person) not welcome, liked
offensive, unacceptable
Cases of word usage
1) the political theory that organized government and laws are undesirable (anarchism)
2) (especially) an official with authority to examine books, magazines, plays, films etc and to remove anything regarded as immortal or in other ways undesirable (censor)
3) to give help or encouragement to a person or thing that is weak, bad or undesirable (pander)