He became frantic when he couldn't find his passport.

frantic 是形容词，意思是"疯狂的、发狂的"，形容因极度焦虑或恐惧而失去理智的状态。这个词来自古法语"frenetique"，最终源自希腊语"phrenitis"（脑炎），表示精神错乱的状态。