One of the first slang terms I came across when I started in the business was “Piker”, as in “so-and-so is a total piker”.
Amongst the brokers, that was the worst name we could call one another, but it could also be used to describe anyone who is involved in or invests in the markets.
Essentially, by calling someone a piker, you were ridiculing them for the fact that they were either a small-time player or too afraid to bet big.
This got me curious enough to start asking about where the term “Piker” came from. Interestingly, those who seemed to use it most often had the least idea of what it truly meant.