Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
dēbellātor, ōris, m. [debello], a conqueror, subduer (rare; mostly poet.): ferarum, * Verg. A. 7, 651; * Stat. Th. 9, 545: Vespasianus Judaeorum debellator, Tert. Apol. 5: durus, Vulg. Sap. 18, 15.