Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
† Synĕphēbi, ōrum, m., = Συνέφηβοι, The Fellow-youths, the title of a comedy by Statius Caecilius, Cic. Fin. 1, 2, 4; id. Sen. 7, 24; id. Opt. Gen. 6, 18.