express mirth

VERB
13 LETTERS · STARTS WITH E

express mirth is a valid 13-letter word worth 26 points in Scrabble and 27 points in Words with Friends.

SCRABBLE WORDS WITH FRIENDS
E1X8P3R1E1S1S1M3I1R1T1H4
1 + 8 + 3 + 1 + 1 + 1 + 1 + 0 + 3 + 1 + 1 + 1 + 4 =26 PTS
DOUBLE WORD → 52TRIPLE WORD → 78
MEANING

What does express mirth mean?