The headword, presumably quoted from somewhere, is the present middle/passive infinitive of the verb noshleu/w, I tend to a sick person: see nu 491, cognate substantives at nu 492, and generally LSJ s.v.
[1] The infinitive in this glossing phrase is the present active form of the verb nose/w, I am ill; see LSJ s.v. The headword is identically glossed in the Synagoge, Photius' Lexicon (nu255 Theodoridis), and Lexica Segueriana 309.28; and cf. Hesychius nu659.