Douglas Harper's Etymology Dictionary
Wiktionary
four-flusher
n. (context slang English) A lowly, disreputable cheat#Noun or fraudster, especially at cards, especially a dull or unimaginative one.
WordNet
four-flusher
n. a person who tries to bluff other people [syn: bluffer]
Usage examples of "four-flusher".
An' then my job'll be to hunt that Saint guy downtake him into the back room of a station house and sweat a confession outa him with a baseball batput him in court an' work like hell to send him to the chairthe guy who only did what you or me would of done if we weren't such lousy, white-livered four-flushers we think more about holding down a paycheck than getting on with the work we're paid to do!
He blew a gasket and called me a cheat and a four-flusher, and a good many other names.