| 不行 | bù xíng | won't do / be out of the question / be no good / not work / not be capable |
| 非得 | fēi děi | (followed by a verb phrase, then – optionally – 不可, or 不行 etc) must |
| 母汤 | mǔ tāng | (Tw) (slang) don't; must not; won't do (from Taiwanese 毋通, Tai-lo pr. [m̄-thang], similar to Mandarin 不要[bu4 yao4] or 不行[bu4 xing2]) |