αἴκα

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 (Liddell-Scott)

αἴκα: [κᾱ], Δωρ. ἀντὶ τοῦ εἴ κε, ἐὰν, ἐξ εἰκασία τοῦ Walck. Θεόκρ. 1.10.

Greek Monotonic

αἴκα: [κᾱ], Δωρ. αντί εἴ κε ή ἐάν, σε Θεόκρ.

Russian (Dvoretsky)

αἴκᾱ: дор. Theocr. = εἰ.

German (Pape)

dor. für εἴκε, ἐάν, Theocr.