Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
mūtātor, ōris, m. [1. muto], a changer; an exchanger, barterer (poet. and post-Aug. prose): mutator circulus anni, i. e. Zodiacus, Luc. 10, 202: mercis mutator Eoae, i. e. mercator, id. 8, 854: equorum, i. e. desultor, Val. Fl. 6, 161: mercium commerciorumque mutator, Arn. 3, 119.