Fast buck

What is a fast buck and where does it comes from?

It's a dollar, a "buck," made by illegal or unethical means, not one earned by the sweat of honest labor. (I was going to say it's a male deer and it comes out of the woods, but I restrained myself.)

Usu acquired quickly

Easy money. Usually through something questionable or downright illegal. The opposite of earned an honest dollar.

origin a speedy young animal?

Li

PS
Rude Boy would has speculated on a particular method of earning one...

LY

If you turn a fast buck, I suspect that may well come from poaching deer. And maybe that is indeed the origin of the buck meaning dollar.

JMM

In the colonial US, buckskin (deer hide--w/o the horns, all deer skin is the same) was as good as cash and used as currency. The going rate for a deer skin in Missoula, Montana is one pair of deer skin gloves. Just go down to the recycling center and they'll give you a new pair of gloves from last year's kill for a wet hide. Anyone with a dog knows this is the only thing to do with a deer skin. It only takes one experience with a dog farting deer fur ----it really smells bad--to swear-off tanning hide, forever