four-flusher [ˈfɔrˌflʌʃər] n.
1.) A pretender, braggart, humbug (O.E.D. 2nd Ed.).
Etymology: In poker, a four flush (also bob-tail flush) is a flush containing only four (instead of five) cards, and hence almost worthless. Thus four-flush as adjective, meaning 'lacking in genuineness', and as intransitive verb, meaning 'to act in a bluffing or fraudulent manner'.
"'Couldn't it have been a suicide?" I asked. With Tim Noonan getting a last-minute bright idea to stick it on Max?'
'That four-flusher shoot himself? Not a chance'" (Red Harvest, Dashiell Hammett, 1929).