κοπροδότης

From LSJ

οὐκ ἂν λάβοις παρὰ τοῦ μὴ ἔχοντος → you can't take from one who doesn't have, you can't squeeze blood out of a turnip, you can't get blood out of a turnip, you can't get blood from a stone, you can't get blood out of a stone

Source

Greek Monolingual

κοπροδότης, ὁ (Μ)
αυτός που κοπρίζει.
[ΕΤΥΜΟΛ. < κόπρος + -δότης (< δότης < δίδωμι), πρβλ. ζωοδότης, φωτοδότης.