glass jaw noun2 •A fighting vulnerability where one is easily knocked out via a single hard blow to the chin or jaw (due to lack of conditioning, insufficient training, or damage from past cerebral concussions)."How was I to know that big ape had a glass jaw?" — 1989 •(figurative) A vulnerability of that sort; a weak spot.It is essential that a player be able to identify his glass jaw or his weak spot and learn to deal with it in actual competition. — 1979 formsglass jaws
