Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
contĭōnātor, ōris, m. [contionor], a haranguer of the people; in a bad sense, a demagogue, a political agitator, Cic. Cat. 4, 5, 9 (opp. animus vere popularis); Front. Ep. ad Ver. 1, p. 171; cf.: contionator, allocutor multitudinis, Isid. Orig. 10, 38.