finny

adj

1. Having one or more fins.

   “The silent fisher […] waits the finny prize (Book XII)”

   “The finny trophies he brought back in the form of numerous fat pickerel were ample evidence of his fishermanship.”

2. Resembling a fin.
3. Abounding in fishes.

   “1730–1774, Oliver Goldsmith, Introductory to Switzerland Cheerful at morn, he wakes from short repose, Breathes the keen air, and carols as he goes; With patient angle trolls the finny deep, Or drives his venturous ploughshare to the steep;”

noun

1. (UK, slang)A five-pound (£5) note; the sum of five pounds.

   “I passed a good many in drapers’ shops, also at tailors’ shops. I never tried jewellers, they’re reckoned too good judges. The notes were all finnies, (5l. notes), and a good imitation.”