Huh this actually makes sense, it strikes directly at the reasons I’ve never wanted to try playing poker. I’m in my fifties and I have a vague idea that there is a hierarchy of hands and that something called a “flush” is probably the winning hand (which is pretty absurd given that the main way I use “flush” is as a verb for disposing of my body’s waste products via the city’s sewage system) but I have absolutely zero grasp of the mechanics of going from “people are dealt hands” to “someone won”, and not enough free cash to play a game people seem to generally insist is absolutely not worth playing if it’s not for money. The levels of analysis hardcore players constantly descend into at the faintest excuse is really unappealing too, filling my brain up with that sounds impossibly tedious.

(Please do not attempt to explain the rules of poker to me in replies unless you are being hilariously wrong.)

Flush also has a meaning of fullness/abundance, "he was flush wish cash", "his face was flush with embarrassment". It can also mean something level to a surface, as in "this should sit flush against the wall".