There are 4 13-letter words that start with 'boo'.
| bookbinderies | bookishnesses |
| boorishnesses | bootstrapping |
Note: These 4 13-letter words that start with 'boo' are found from the USA & Canada version of the tournament Scrabble word list.
Also see words start with book, boot, boom, boog, boob, boon, booz, boos, bood, boor, booh, booc, booj, booe, booi.
4-letter words start with 'boo' (7)