coup de main

NOUN
12 LETTERS · STARTS WITH C

coup de main is a valid 12-letter word worth 17 points in Scrabble and 22 points in Words with Friends.

SCRABBLE WORDS WITH FRIENDS
C3O1U1P3D2E1M3A1I1N1
3 + 1 + 1 + 3 + 0 + 2 + 1 + 0 + 3 + 1 + 1 + 1 =17 PTS
DOUBLE WORD → 34TRIPLE WORD → 51
MEANING

What does coup de main mean?