Third person plural, imperfect indicative active, of the verb kompolake/w. Glossed differently in a scholion on Aristophanes, Frogs 961 (where the headword is first person singular, spoken by Euripides: see web address 1, and omicron 866). If the present instance is, truly, third person plural, it must be quoted from somewhere else; but we may suspect a miscontruing.
cf. also kappa 2018.