Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
convictor, ōris, m. [convivo], he who lives with one, a table companion, messmate, familiar friend, Cic. Fil. ap. Cic. Fam. 16, 21, 5; Hor. S. 1, 4, 96; 1, 6, 47; Plin. Ep. 2, 6, 4; Sen. Ep. 7, 5; id. Ira, 3, 8, 2; id. Lud. Mort. Claud. 14, 2; Suet. Vit. Hor.