Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
vĭtŭpĕrātor, ōris, m. [1. vitupero], a blamer, censurer, vituperator: invidos vituperatores confutare, Cic. N. D. 1, 3, 5: philosophiae, id. Fin. 1, 1, 2; id. Tusc. 2, 2, 4: vituperatores mei, id. Fam. 7, 3, 6.