Function
Must
Must noun - Something necessary, indispensable, or unavoidable.
Mutual synonyms
How words are described
| real | real function | real must |
| main | main function | main must |
| military | military function | military must |
| optional | optional function | optional must |
Common collocations
Both words in one sentence
-
In Firefly, how Serenity's engines function is never explained, other than it must spin to work.
- You must use the other button with a similar function, the "A" button against the tree, ensuring that you open your inventory and not "talk" to the tree.
Source: Guide Dang It / Strategy - If someone lasts longer than their first bad call, anyone who works as an emergency medical responder will eventually experience this, as they must in order to function.
Source: It Gets Easier
Cite this Source
Must and Function. (2016). Retrieved 2026, July 21, from https://thesaurus.plus/related/function/must
Function & Must. N.p., 2016. Web. 21 Jul. 2026. <https://thesaurus.plus/related/function/must>.
Must or Function. 2016. Accessed July 21, 2026. https://thesaurus.plus/related/function/must.
Google Ngram Viewer shows how "function" and "must" have occurred on timeline