fluke

noun

1.
a stroke of luck
good fortune good luck
Derived from:
flukey fluky
2.
a barb on a harpoon or arrow
3.
flat bladelike projection on the arm of an anchor
flue
4.
either of the two lobes of the tail of a cetacean
5.
parasitic flatworms having external suckers for attaching to a host
trematode trematode worm