Entry lacking, Adler reports, in ms A.
The headword, evidently extracted from somewhere (but unattested outside lexicography), is the third person singular, pluperfect indicative middle/passive, of the compound verb sune/rgw, I shut up, enclose, fasten together; cf. sigma 1504 and see generally LSJ s.v.
[1] The first gloss is imperfect middle/passive of the verb sumfula/ssw, I keep watch and ward together, guard together; see generally LSJ s.v. The second gloss is pluperfect middle/passive of the contract verb sunde/w, I bind, tie together; cf. the present middle/passive infinitive at sigma 1476 and see generally LSJ s.v. Identical glossing in the Synagoge (sigma336), Photius (Lexicon sigma760 Theodoridis), and cf. already Hesychius sigma2487 (glossing simply with e)de/deto).