How to Spell must
must
must - verb
- Be commanded or requested to
Source: Merriam-Webster Dictionary API
"you must stop"
Etymology
Middle English {it}moste{/it}, from Old English {it}mōste{/it}, past indicative & subjunctive of {it}mōtan{/it} to be allowed to, have to; akin to Old High German {it}muozan{/it} to be allowed to, have to
From Old English 'mōste'
Word family
mustn't