piker
A soldier armed with a pike, a pikeman.
historical
Upstairs in a waiting room there were pikers whose tunics echoed Baudricourt′s gold lion shield painted up and down the rafters.
One who bets or gambles only with small amounts of money.
“[…] Them rich fellers, they don't make no bad breaks with their money. They watch it all th' time b'cause they know blame well there ain't hardly room fer their feet fer th' pikers an' tin-horns an' thimble-riggers what are layin' fer 'em. […]”
A stingy person; a cheapskate.
“And if you′ve got to be a piker,” said Dolly, “don′t be ashamed to be a piker. We′re not spending a hundred dollars because we can afford it, but because you dreamt a dream.”
An amateur.
Where it comes from
From pike + -er. In some senses, it has been linked etymologically to the word pikey as well as to Pike County in eastern Missouri https://web.archive.org/web/20051111194645/http://www.yourdictionary.com/ahd/p/p0300200.html. In the latter instance the term originally denoted poor immigrants to California.
Adapted from the Wiktionary entry piker (CC BY-SA 4.0).