The headword is the present active indicative, third person singular, of the verb neike/w, I quarrel/wrangle with; see LSJ s.v. It occurs at, and is quoted from, Homer, Iliad 1.521 (web address 1): Zeus complains to Thetis that Hera constantly quarrels with him.
cf. generally nu 283, nu 286.
[1] The glosses are the same form as the headword. The first is from the verb ye/gw, I blame, censure; see LSJ s.v. The second is from the verb filoneike/w, I am fond of strife; see LSJ s.v. The headword is identically glossed in the Synagoge, Photius' Lexicon (nu92 Theodoridis), and Lexica Segueriana 307.3; cf. ps.-Herodian, Partitiones 92.8. Apion evidently extracts neikei=n, the headword verb's present active infinitive, from Homer, Iliad 20.254 (web address 2) and provides as gloss filn, the corresponding infinitive for the second gloss. Adler also cites the lexicon of Codex Laurentianus 59.16.