么

么 never stands alone. It is a bound suffix that builds the core question and degree words: 什么 (what), 怎么 (how/why), 那么 / 这么 (that much / this much), 多么 (how X!), 要么 (either…or). Always toneless. If you see it standing alone in a sentence, you have probably mis-segmented.

Think of 么 as the little tail that turns plain words into question words: 什 + tail → 'what?', 怎 + tail → 'how?', 这 + tail → 'this much!'. Drop the tail and the stem has no everyday meaning.

Older texts and some dialect writing use 么 as a sentence-final question particle and rarely as an exclamatory 么. Modern standard writing handles both jobs with 吗 (yes/no questions) and 嘛 (obvious-fact / coaxing tone), so you can safely treat 么 as the suffix reading and leave the final-particle role to those two characters.