There are 10 11-letter words that start with 'fir'.
| fireballers | fireballing | firebombing | 
| firecracker | firefanging | firefighter | 
| fireproofed | firmamental | firstfruits | 
| firstnesses | ||
Note: These 10 11-letter words that start with 'fir' are found from the USA & Canada version of the tournament Scrabble word list.
Also see words start with fire, firm, firs, firr, firi, firk, firn, firt.
4-letter words start with 'fir' (4)