(adj) means annoying in a particularly vulgar and cheeky way. To be rude, insulting, and offensive. It is often used to refer to something intentionally oversized or intentionally offensively loud. Bragging is considered obnoxious, as is intentionally disregarding a rule. Showing off your disregard for a rule or order. Being blatantly disrespectful of social norms and those who would enforce them.

People who are overly loud, sometimes offensive, & almost always irritating; will give you the compulsion to tear your own ears off to shove them down their throat.

the kind of people u wanna shoot in the head..

annoying/demanding

Annoying; Pesky; Pain in the neck; Bothersome

–adjective
1. highly objectionable or offensive; odious: obnoxious behavior.
2. annoying or objectionable due to being a showoff or attracting undue attention to oneself: an obnoxious little brat.
3. Archaic. exposed or liable to harm, evil, or anything objectionable.
4. Obsolete. liable to punishment or censure; reprehensible.

insulting vulgar and rude, someone who adds insult to injury by blatantly disregarding social rules or customs.

vulgar, oversized or offensively loud

cheeky, one who parades their non compliance and brags about disrespecting those in charge