adverb, verb · placed after a verb like 吃 chī or 喝 hē to indicate that one is unable to ingest more food or drink due to fullness, illness, or emotion

我心里难受，实在吃不下。

adverb · to be not less than a certain quantity or amount

参加这次会议的人数不下五十人。

verb, adverb · used after a verb (like 装 zhuāng or 坐 zuò) to indicate that a space is too small to accommodate more of something or someone

书架太小，这些书装不下。