The headword, evidently quoted from somewhere, is accusative singular of the noun mo/sxos. LSJ distinguishes between three such nouns: (A) young shoot or twig, (B) calf, young bull, and (C) musk. Given the gloss here (for which compare e.g. tau 335, psi 2), the present entry can be assumed to be an instance of A; for the vocabulary cf. mu 1273.
[1] The gloss is an adjective (a(palo/s, -h/, -o/n; see LSJ s.v.) in the masculine accusative (and neuter nominative/vocative/accusative) singular. The headword is identically glossed in Photius' Lexicon (mu549 Theodoridis), Synagoge mu275, and Lexica Segueriana 303.27; cf. cognates at mu 1273, mu 1274, mu 1275, and mu 1276.