expression
unforgivable; inexcusable; unpardonable
A fixed, somewhat old-fashioned or emphatic expression meaning 'should not be forgiven' or 'unforgivable'. Often used in dramatic or literary contexts.
彼の裏切りは許すまじ行為だ。
His betrayal is an unforgivable act.
このような不正は許すまじ。
Such injustice is inexcusable.