A.T. Robertson Commentary Matthew 27:44

"And the robbers also that were crucified with him cast upon him the same reproach." — Matthew 27:44 (ASV)

The robbers also (κα ο ληιστα). Probably "even the robbers" (Weymouth) who felt a momentary superiority to Jesus thus maligned by all. So the inchoative imperfect ωνειδιζον means "began to reproach him."