obnoxious

Obnoxious means so loud and unpleasant that everyone is annoyed. An obnoxious man, obnoxious behaviour, utterly obnoxious.

It is a strong criticism of a person rather than an act, and it implies the offence is deliberate or at least careless. It is commoner in American English than British. Note that the word once meant vulnerable or exposed to harm — obnoxious to injury — which is the opposite direction entirely, and that older sense is now dead outside legal writing.