trim down

VERB
9 LETTERS · STARTS WITH T

trim down is a valid 9-letter word worth 14 points in Scrabble and 16 points in Words with Friends.

SCRABBLE WORDS WITH FRIENDS
T1R1I1M3D2O1W4N1
1 + 1 + 1 + 3 + 0 + 2 + 1 + 4 + 1 =14 PTS
DOUBLE WORD → 28TRIPLE WORD → 42
MEANING

What does trim down mean?