There are 15 10-letter words that start with 'moo'.
| mooncalves | moonfishes | moonflower | 
| moonlights | moonquakes | moonscapes | 
| moonshined | moonshiner | moonshines | 
| moonstones | moonstruck | moonwalked | 
| moosebirds | moosewoods | mootnesses | 
Note: These 15 10-letter words that start with 'moo' are found from the USA & Canada version of the tournament Scrabble word list.
Also see words start with moon, moor, mood, mool, moot, mooc, moos, mooe, mooi.
4-letter words start with 'moo' (6)