ὑποψιθυρίζω
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
English (LSJ)
A whisper softly, of fingers on the lyre, Ach.Tat.1.5.
Greek (Liddell-Scott)
ὑποψῐθῠρίζω: ψιθυρίζω ἠρέμα, ἡ παρθένος παρατιθεμένη μοι τὸ ποτήριον, χαίροις, ὑπεψιθύρισεν Εὐμάθ. 1. 8.