Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
com-mănĭpŭlo, ōnis, m., a comrade of the same manipulus, Spart. Nig. 10, 5.
So also ‡ COMMANIPVLVS and COMMANIPLVS, Inscr. Orell. 3557; Inscr. Grut. 551, 1.