ὑποκρούω · hypokrouō — LSJ
strike gently, [λίθον] χερμάδι APl. 16.279; beat time, give the time, Plu. Dem. 20; ὑ. τοῖς λέγουσι Longin. 41.2.
sens. obsc., Ar. Ec. 256 (with play on signf. II.1), 618 (anap.).
metaph., break in upon, interrupt, c. acc., Id. Ach. 38, Ec. 588 (anap.), Alex. 32, Henioch. 5.4, Plb. 18.4.3: abs., ὑποκρούσας (sc. εἶπε) Pl. Erx. 395e.
ὑπέσχοντο εἰς τὰ μηνιαῖα αὐτοῦ ὑποκροῦσαι ταύτην τὴν δόσιν to credit this payment to his monthly account, PFlor. 132.10 (iii A. D.).
in Med., find fault with, attack, Ar. Pl. 548 (anap.).