[1] According to LSJ, tetrhxui=a has been determined to be the epic perfect active participle, feminine singular nominative, of tara/ssw = stir up (web address 1). As the headword here, it is almost certainly extracted from Homer, Iliad 7.346 (an assembly in confusion/uproar: web address 2), a scholion to which provides a similar gloss. LSJ note that "Alexandrine and later Poets seem to have thought erroneously that te/trhxa = to be rough (cf. traxu/s)." Glossing in terms of tara/ssw is provided by the Synagoge (tau124 Cunningham) and Photius (Lexicon tau199 Theodoridis).
[2] Quoted from Homer, Iliad 2.95 (where again it describes emotional turmoil at a mass meeting); cf. the scholia ad loc., epsilon 3302, and Hesychius tau646.