highly objectionable or offensive; odious

obnoxious behavior.

annoying or objectionable due to being a showoff or attracting undue attention to oneself

an obnoxious little brat.

Archaic . exposed or liable to harm, evil, or anything objectionable.

Obsolete . liable to punishment or censure; reprehensible.

adjective

agreeable , delightful , kind , likeable , nice , pleasant , soft

adjective

abhorrent , abominable , annoying , awful , beastly * , big mouth , detestable , disagreeable , disgusting , dislikable , displeasing , foul , gross * , hateable , hateful , heel , horrid , insufferable , invidious , loathsome , mean , nasty , nauseating , objectionable , odious , off-color * , ornery , pain in the neck * , pesky * , pestiferous , pill * , repellent , reprehensible , repugnant , revolting , rotten , sickening , stinking , unpleasantnotes:noxious means injurious to physical or mental health; obnoxious means very offensive , or unpleasant , antipathetic , contemptible , despicable , despisable , infamous , lousy , low , nefarious , shabby , vile , wretched , liable , loud , offensive , repulsive , subject , unpleasant