Unhinge began as a very physical word: to take a door off its hinges, so that it no longer hangs properly and swings loose. That picture is the key to everything else. When English uses it about a person, it means to disturb someone's mind so badly that they lose their balance — grief, shock or long strain knocks them off their hinges. The event unhinged him. It is a strong word and not a gentle one; it describes real mental breakdown, not ordinary sadness or stress. In practice you will meet the past participle unhinged far more often than the plain verb, and unhinged as an adjective describes someone whose behaviour has gone wild, irrational or frightening: an unhinged rant, he sounded completely unhinged. It can be used about things too — an unhinged theory, unhinged policy — meaning wildly illogical. There is one more thing your students should know, because it is everywhere online now: among younger speakers unhinged has flipped into a compliment. "That advertisement is unhinged" or "her comedy is completely unhinged" now often means gloriously chaotic, too much in the best way, hilariously beyond normal limits. That newer use is playful and admiring, and it lives mostly in internet and youth speech, while in a news report or a novel the old darker meaning still holds. Same word, and the audience tells you which meaning is meant.

使精神錯亂、使崩潰（原意是「把門從鉸鏈上卸下來」）。注意 unhinged 在年輕人／網路用語裡已轉成褒義，指「瘋得很精彩、超展開」，跟原本「發瘋、失控」的負面語感要分開看。