
Egomaniac
Negative Connotation
The term 'egomaniac' implies strong negativity and is used to criticize or disapprove someone's behavior. 
Informal Usage
'Egomaniac' is informal and might be seen as rude or insensitive if used in professional or polite conversations. 
Humor or Sarcasm
Sometimes 'egomaniac' is used humorously or sarcastically among friends or in casual settings. 