The headword is a post-classical spelling of the present indicative middle, third person plural, of the verb ti/numai (I punish, chastise, take vengeance); cf. tau 642 and see generally LSJ s.v. As transmitted here with -nn-, the form of the lemma is first attested (C1-2 CE) at, and may be generated from (but see next note), an identical entry at Apollonius Sophistes, Homeric Lexicon 153.7.
[1] The gloss is the present indicative middle/passive, third person plural, of the contract verb timwre/w, I avenge, exact vengeance; cf. tau 657 and see generally LSJ s.v. The headword is identically glossed at Hesychius tau928 Cunningham/Hansen, which cites as a source ti/nuntai at Homer, Iliad 19.260 (web address 1; cf. the D scholia thereto): Agamemnon swears an oath to Zeus and the Erinyes, the latter who take vengeance (ti/nuntai) on human beings, that Briseïs remained untouched in his hut. Identical entries also at Synagoge tau185 and Photius, Lexicon tau315 Theodoridis; similar ones at e.g. ps.-Herodian, Partitiones 132.11; ps.-Zonaras, Lexicon tau1734; Etymologicum Magnum 759.17 (Kallierges); Etymologicum Gudianum alpha164.10 (end).