noun
suicidal act; self-destructive action
Refers to an action that is extremely dangerous or reckless, as if inviting death or ruin. Often used figuratively for actions that are likely to lead to severe negative consequences.
飲酒運転は自殺行為だ。
Drunk driving is a suicidal act.
そんな無謀な計画は自殺行為に
Such a reckless plan is tantamount to a suicidal act.