have a fit

VERB
10 LETTERS · STARTS WITH H

have a fit is a valid 10-letter word worth 17 points in Scrabble and 17 points in Words with Friends.

SCRABBLE WORDS WITH FRIENDS
H4A1V4E1A1F4I1T1
4 + 1 + 4 + 1 + 0 + 1 + 0 + 4 + 1 + 1 =17 PTS
DOUBLE WORD → 34TRIPLE WORD → 51
MEANING

What does have a fit mean?