There are 16 8-letter words that start with 'mut'.
| mutagens | mutating | mutation | mutative | 
| mutchkin | muteness | muticous | mutilate | 
| mutineer | mutinied | mutinies | mutining | 
| mutinous | muttered | mutterer | mutually | 
Note: These 16 8-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)