Yes, haw is a Scrabble word!
...and is worth 9 points in Scrabble, and 8 points in Words with Friends
haw
Verb
1. Utter `haw'
Noun
1. A spring-flowering shrub or small tree of the genus Crataegus
2. The nictitating membrane of a horse
What Scrabble words can I make with the letters in haw?
3 Letter Words
2 Letter Words