Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
The word iustificator could not be parsed. Trying a normal dictionary lookup:
justĭfĭcātŏr, ōris, m. [justifico], he who justifies (eccl. Lat.), August. de Spir. et Lit. 26; id. ib. 29.