σκιαμαχέω
From LSJ
πωγωνοτροφία φιλόσοφoν οὐ ποιεῖ → a long beard does not make the philosopher
English (LSJ)
A fight against a shadow, i.e. an imaginary opponent, and so, spar, Posidon.16 J., Plu.2.130e, Paus.6.10.3: πρὸς τὸν οὐρανὸν σκιαμαχῶν sparring with the sky, 'baying at the moon', Cratin. 17 (lyr.). II metaph., Pl.Ap.18d; πρὸς ἀλλήλους Id.R.520c; πρὸς ἡμᾶς αὐτούς Id.Lg.830c; πρὸς τὸν οὐκέτι ἐν ζῶσιν ὄντα Πλάτωνα ἐσκιαμάχει Numen. ap. Eus.PE14.6:—Pass., ἔπη μάτην σκιαμαχούμενα thrown out at random in disputations, Luc.Pisc.35.—σκιομαχέω is a later form in codd. of Ph.1.356, Antyll. ap. Orib.6.29.3.