An unreasonably thrifty person. (Flint is a semiprecious mineral a relative of quartz, and the notion that the greediest person would keep flint shavings for economy).
An expression to describe someone who claims to be skint all the time to avoid spending cash when they are actually minted.
Eg 1
James: Do you think Jeremy will want to come to the cinema?
Jacob: Yeah he will but he'll pull the whole skintminted routine.
James: That's true, he'll want to wait for orange wednesdays.
Eg 2
Jeremy: Dude, I'm gonna have to ask for some diesel money, really struggling for cash at the minute.
Isaac: *cough* skintminted *cough*
Jeremy: What did you say?!
Isaac: Nothing just clearing my throat.