mussed / must are similar-sounding terms with different meanings (referred to as homophones). To better understand the differences, see below for definitions, pronunciation guides, and example sentences using each term. 👇
mussed: (verb) make messy or untidy.
must: (noun) a necessary or essential thing. (noun) grape juice before or during fermentation. (adjective) highly recommended.
mussed: NA
must: m·AH·s·t
(Examples are Wikipedia snippets under the CC ShareAlike 3.0 license. Definitions drawn from WordNet.)