financial suicide refers to one's personally fatal mistake that ruined their chances of ever making/saving money and permanently cements them in poverty, and along with it their possibility of earning a good living ever again.
employee 1:hey dude, i invested all my savings into (insert terrible investment opportunity that totally won't financially ruin you) and i put in my two weeks notice to my boss, and its rather smelly especially sense its on his desk. soon I'll be living super rich.
Employee 2: uhhh dude, that stock just Crashed.
Employee 1: what? NOooo!! that was my entire Life savings!!
Employee by the copy machine: and that dude just committed financial suicide, ouch!