There are 14 9-letter words that start with 'mut'.
| mutagenic | mutations | mutchkins | 
| mutilated | mutilates | mutilator | 
| mutineers | mutinying | mutterers | 
| muttering | mutualism | mutualist | 
| mutuality | mutualize | |
Note: These 14 9-letter words that start with 'mut' are found from the USA & Canada version of the tournament Scrabble word list.
Also see words start with muti, muta, mutu, mutt, mute, mutc, muto, muts.
4-letter words start with 'mut' (3)