Mace

The Caretakerの主人公のJosephは仕事を首になります。
Twyman's wife drives him north in a sleek, silent truck, the wipers slipping smoothly over the windshield. She keeps one hand in her purse, clenched around what Joseph guesses to be Mace or perhaps a gun. She thinks I am an idiot, thinks Joseph.
"perhaps a gun" と書かれていますから "Mace" も何か物騒なの様です。辞書を見ます。
・Oxford English Dictionary: trademark: An irritant chemical used in an aerosol to disable attackers.: You can't pull your gun, no Mace - why don't we just arm-wrestle to see if you go to jail?
・Merriam-Webster's Online Dictionary: used for a liquid that stings the eyes and skin and that is used as a spray to defend against an attacker: She maced the man who attacked her.
大文字で始まっているので商標から来た単語だと分かりますが、小文字の "mace" に元々こんな意味がありました。
・Merriam-Webster's Online Dictionary: a heavy often spiked staff or club used especially in the Middle Ages for breaking armor