To be obliged to; to be required or compelled to.
Contributed by ASLwrite, 2016 for "must".
Instead of using one finger, it uses the whole fingers to mean 'very must' or 'must!!!' as sometimes seen in spoken ASL.
Jolanta experimented two different handshapes (the older digit on the left and newer digit on the right) along with the mouth morpheme (intense). Below the digits is the fingerspelled word, "MUUUUST".
Contributed by Jolanta in the ASLwrite community, 2017.