The headword -- third person plural, aorist indicative active, of o)/zw -- is quoted from Exodus 8:14 LXX, where it is used of the aftermath of the plague of frogs. The gloss simply explicates the simple verb with one of its attested compounds. (For prosw/zesan cf. e.g. Psalms 37:6 LXX, and again under pi 2759.) See LSJ entries for the two verbs at web addresses 1 & 2.