συναίρεσθαι
From LSJ
αἱ δὲ χολωσάμεναι πηρὸν θέσαν → but they in their wrath maimed him, but they in their wrath made him helpless, but they in their wrath made him blind
Greek > English (Woodhouse Verbs Reversed)
(see also συναίρω): take a share in, take part in, undertake with another