What it means
A tightfisted miser so stingy they would, as the old joke goes, skin a flint to save the scrap. The flint is already the hardest, least giving of stones, so anyone trying to peel it for profit is mean to a comical degree. The undisputed champion of not spending a single penny.
Usage examples
"The old skinflint left a fortune in the bank and yet never once turned the heating above sixteen degrees."
"The old skinflint reuses teabags and turns the heating off in November."
"Do not be such a skinflint, it is your round and the drinks are not that dear."
"He's such a skinflint he brought his own teabag to the hotel breakfast and took the little jam pots home."
"Don't ask that skinflint to chip in for the taxi, he'll suddenly remember he's only got exact change for the bus."
Where it comes from
Skinflint has been in English since the early 18th century. It joins skin with flint, built on the absurd image of trying to skin a stone to squeeze some tiny scrap of value from it. That comic picture stuck, and the word came to mean someone mean with money far past ordinary thrift.
Other ways to say it
This expression also appears in