Same entry in other lexica. The headword is either present indicative (third person plural) or present participle (masculine/neuter dative plural) of the compound verb diakuka/w.
Apart from its occurrence in Demosthenes 18.111 (diakukw=n, applied by Demosthenes to Aeschines), forms of this verb -- including this form -- appear in greatest numbers in Cyril of Alexandria.