Answer:

fluke

Answer	Crossword Clue
FLUKE	Stroke of luck
FLUKE	Stroke of good luck
FLUKE	Winning the lottery, say

FLUKE	Lucky shot
FLUKE	Lucky break
FLUKE	Unlikely stroke of luck
FLUKE	Quirk of fate
FLUKE	Accidental success
FLUKE	Harpoon barb.
FLUKE	An accidental success: Colloq.
FLUKE	Stroke of luck.

FLUKE	Lucky chance.
FLUKE	Part of a whale's tail.
FLUKE	Lucky chance: Slang.
FLUKE	Stroke of luck: Slang.
FLUKE	Lucky chance
FLUKE	Outlandish bit of luck
FLUKE	Summer flounder
FLUKE	Accidental stroke of luck

FLUKE	Bit of serendipity
FLUKE	Result of careful planning it's not
FLUKE	Hole in one, assuredly
FLUKE	Sushi offering
FLUKE	A stroke of luck
FLUKE	Chance happening
FLUKE	Serendipitous occurrence
FLUKE	Happy accident