Synonyms for Obnoxious:

adj.

bad (adjective)
unpleasant.
disagreeable (adjective)
distasteful, disagreeable, bothersome, unpalatable, disgusting, unpleasant, repulsive, offensive, nasty.
hateful (adjective)
loathsome.
objectionable (adjective)
objectionable.
offensive (adjective)
displeasing, annoying, offensive, study at offensive.
offensive, repulsive (adjective)
displeasing, annoying, reprehensible, disgusting, unpleasant, rotten, loathsome, abominable, nasty, disagreeable, objectionable, foul, repugnant, abhorrent, mean, odious, detestable.
wicked (adjective)
debauched, felonious, wicked, degenerate, debased, criminal, immoral, blameworthy, sinister, improper, wrongdoing, black, scandalous, base, sinful, shocking, bad, perverse, iniquitous, Misdoing, reprehensible, lawbreaking, depraved, evildoing, damnable, indecent, corrupt, sadistic, villainous.

n.

impertinent, discourteous, abrasive, rude, ill-mannered, smart, insolent, impudent, impolite. obnoxious (noun)
objectionable, unpleasant, offensive.

Other synonyms:

Despisable. detestable, abhorrent, despicable, abominable, contemptible, vile, repugnant, lousy, odious, nefarious, loathsome. infamous, antipathetic, wretched, shabby. filthy. low. rotten. foul. objectionable
objectionable.
Other relevant words:
impertinent, annoying, foul, detestable, lousy, loathsome, nefarious, despicable, low, infamous, mean, displeasing, repugnant, insolent, objectionable, odious, abhorrent, rude, shabby, antipathetic, Despisable, contemptible, abominable, vile, rotten, filthy, wretched.

Usage examples for obnoxious

  1. A course thus independent, and in harmony with the policy of the administration, caused Mr. Adams to become obnoxious to suspicions inevitably incident to every man who, in critical periods, amid party struggles, changes his political relations. – Memoir of the Life of John Quincy Adams. by Josiah Quincy
  2. We swept on, and I felt that I was highly obnoxious to Camilla. – Great Expectations by Charles Dickens