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to come off; to slip down; to slip off
走っていたら靴が脱げた。
My shoe came off as I was running.
歩くたびにサンダルが脱げてしまう。
My sandals keep slipping off with every step.
今日は風が強くて帽子が脱げるかもしれない。
The wind is strong today, so my hat might blow off.