I used the word "piker" today in Contracts class, to denote a person who was below-average or mediocre at their avocation. The professor had never heard of it -- she asked if it was football term. After class I asked around: most people hadn't heard the term; one person who had defined it as someone who was a cheapskate or who gambles only for small amounts of money. Wiktionary verifies their definition, as well as my own through the third definition, an "amateur".
Is this word very uncommon? It didn't occur to me when I said it I was saying anything regional or obscure, but I gather than it's not a well known term.