πικραίνω

A. make sharp or keen, esp. to the taste, π. τὴν κοιλίαν make it bitter, Apoc. 10.9 :— Pass., τὸ στόμα πικραίνεται Hp. Acut. 30: opp. γλυκαίνεσθαι, Arist. Ph. 244b20.

2. metaph., embitter, irritate, τὴν ψυχήν LXX Jb. 27.2; τὴν ἀκοήν affect it harshly, opp. γλυκαίνω, D.H. Comp. 12, 15; make harsh, νόμους cj. in A. Eu. 693 :—Pass., to be exasperated, embittered, Pl. Lg. 731d, Theoc. 5.120; ὁ ζωγράφος πονεῖ τι καὶ π. vexes himself, Antiph. 144.3; π. ἐπί τισι LXX Ex. 16.20; ἔν τισι ib.Ru. 1.20; also ἐπικράνθη μοι it grieved me, ib.13.

3. of style, make harsh or rugged, διάλεκτον D.H. Dem. 55, cf. 34.