The unglossed primary headword is present active participle, genitive singular masculine/neuter, of the verb sbe/nnumi (for which see also sigma 170). The only other attestation of this form is in Origen, Commentary on the Gospel of John 6.2.10.
The entire entry, Adler reports, is lacking in mss AFV, but is added (after sigma 169) by a later hand in ms A.
[1] Present active indicative, first person singular, of the same verb (in its thematic variant form); probably a generic lexical reference, although the form does have a handful of literary attestations (e.g. John Chrysostom, PG 49.315.51, 57.409.38) For the syntactical information Adler cites Syntacticum Gudianum.
[2] Present active participle, nominative singular feminine, of this same verb. It is presumably quoted from somewhere; attestations include John Chrysostom (PG 59.183.33), Theodoret (PG 83.664.54), and the anonymous Life of St. Irene, Abbess of Chrysobalanton 46.