The headword is a (masculine?) second declension noun in the nominative singular. It is attested only in lexicography -- but see phi 623, and further below.
In her critical apparatus Adler reports that mss GM lack this entry.
[1] The first gloss, ko/pros, is a feminine noun in the nominative singular; see generally LSJ s.v., and cf. kappa 2059, kappa 2060. The second gloss, xw=ma, is a neuter noun in the nominative (and vocative and accusative) singular; see generally LSJ s.v. chi 426, chi 427. The headword is identically glossed in Lexica Segueriana 411.26, the Synagoge, and Photius' Lexicon (where Theodoridis regards the correct form of the headword as foruto/s); cf. Hesychius s.v. fwruto/n, with gloss the accusative singular form surfeto/n of surfeto/s, o( (see LSJ s.v.), anything dragged together, refuse, litter.