headcase

listen to the pronunciation of headcase
İngilizce - İngilizce
A mentally unbalanced, unpredictable person, especially one who displays aggressive behavior

A stockbroker doesn't have 80,000 people sitting behind him just waiting for a mistake, says Jim Fassel, whom fans serenaded with Fire Fassel! chants during his final weeks as head coach of the New York Giants last season. It can drive you crazy. From head coach to head case in three easy steps.

{i} (Slang) lunatic, crazy or deranged person; one who behaves oddly; person who is very foolish; one who is violent; offensive term that intentionally shows contempt for a person's mental state
a violent, mentally unbalanced and unpredictable person
a crazy person
headcase