fast of the firstborn

NOUN
21 LETTERS · STARTS WITH F

fast of the firstborn is a valid 21-letter word worth 32 points in Scrabble and 33 points in Words with Friends.

SCRABBLE WORDS WITH FRIENDS
F4A1S1T1O1F4T1H4E1F4I1R1S1T1B3O1R1N1
4 + 1 + 1 + 1 + 0 + 1 + 4 + 0 + 1 + 4 + 1 + 0 + 4 + 1 + 1 + 1 + 1 + 3 + 1 + 1 + 1 =32 PTS
DOUBLE WORD → 64TRIPLE WORD → 96
MEANING

What does fast of the firstborn mean?

NOUN · 1 SENSE
1

(Judaism) a minor fast day on Nissan 14 that is observed only by firstborn males; it is observed on the day before Passover.