κρουστέον
From LSJ
τὸν αὐτὸν ἔρανον ἀποδοῦναι → pay him back in his own coin, repay him in his own coin, pay someone back in their own coin, pay back in someone's own coin, give tit for tat, pay back in kind
English (LSJ)
one must knock at, τηνδεδί (sc. θύραν) Ar.Ec.989.
French (Bailly abrégé)
adj. verb. de κρούω.
Greek (Liddell-Scott)
κρουστέον: ῥημ. ἐπίθ., δεῖ κρούειν, τὴν θύραν Ἀριστοφ. Ἐκκλ. 989.
Russian (Dvoretsky)
κρουστέον: adj. verb. к κρούω.
Dutch (Woordenboekgrieks.nl)
κρουστέον, adj. verb. van κρούω, er moet gebeukt worden.