ματαιόφρων
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)
ὁ, ἡ, gen. φρονος, weak-minded, LXX 3 Ma.6.11, Adam.2.24.
Greek (Liddell-Scott)
μᾰταιόφρων: ὁ, ἡ, ὁ μάταια, ἀνόητα φρονῶν, ἄφρων, ἀνόητος, Ἑβδ. (Γ΄ Μακκ. ϛʹ, 11), Κλήμ. Ἀλ. 18.
Greek Monolingual
(Α ματαιόφρων, -ον)
αυτός που σκέφτεται μάταια και ανόητα, άμυαλος, απερίσκεπτος.
[ΕΤΥΜΟΛ. < μάταιος + -φρων (< φρην, φρενός)].
German (Pape)
ον, törichtes, eitles Sinnes, Clem.Al., LXX. und andere Spätere