Sense

1. water in which the hands have been washed, dirty water

Examples

• ἀλλ’ ὁ Κοισύρασ καὶ Λάμαχοσ, οἷσ ὑπ’ ἐράνου τε καὶ χρεῶν πρώην ποτέ, ὥσπερ ἀπόνιπτρον ἐκχέοντεσ ἑσπέρασ, ἅπαντεσ ἐξίστω παρῄνουν οἱ φίλοι. (Aristophanes, Acharnians, Lyric-Scene, strophe 2 1:45)
• ἐκάλουν δ’ ἀπόνιπτρον τὸ ἀπόνιμμα τῶν χειρῶν καὶ τῶν ποδῶν. (Athenaeus, The Deipnosophists, Book 9, book 9, chapter 781)
• ὥσπερ ἀπόνιπτρον ἐκχέοντεσ ἑσπέρασ. (Athenaeus, The Deipnosophists, Book 9, book 9, chapter 783)

Source: Henry George Liddell. Robert Scott. "A Greek-English Lexicon". revised and augmented throughout by. Sir Henry Stuart Jones.