Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
apprŏbātor (adp-), ōris, m. [approbo], one who gives his assent or approval, an approver (perh. only in the two foll. exs.): quamvis non fueris suasor et impulsor profectionis meae, adprobator certe fuisti, * Cic. Att. 16, 7, 2: verbi, * Gell. 5, 21, 6.