The headword (evidently quoted from somewhere) is the present active participle, masculine nominative singular, of the verb mosxeu/w (I plant a young shoot); cf. mu 760, mu 1273 and LSJ s.v. This verb appears as part of an uncommon compound, in the third person plural imperfect, in the quotation that follows.
[1] Same gloss in the Synagoge, Photius' Lexicon (mu547 Theodoridis), and Lexica Segueriana 303.25; similar one already in Hesychius mu1710.
[2] Eunapius fr.92 FHG (4.53); cf. Blockley, pp.124-5. Bernhardy suggested e)mo/sxeuon (they were planting young shoots, i.e. the seeds of war) instead of u(pemo/sxeuon. Kuster proposed u(pe/trefon (they were slowly growing).