stab in the back noun 1verb 1forms 3 noun1 •An act of betrayal or treachery.Vice-President Dick Cheney viewed the move by Britain—“perfidious Albion,” as he put it—as “a stab in the back,” according to a former senior intelligence official. — 2009 verb1 •To betray (somebody). formsstabbed in the back · stabbing in the back · stabs in the back