In his seminal contribution on "Etymology and the Old Testament", J. Barr wrote: "Etymology is particularly important for the identification and elucidation of rare words and hapax legomena. The Hebrew Bible has many such rare words, and these can often be elucidated only through comparison with words in Ugaritic, Akkadian, Arabic and other cognate languages". In practice, one often observes that even the Septuagint (LXX) is used as a source for the etymological reconstruction of problematic Hebrew terms. However, although the LXX is undoubtedly a very ancient textual witness, this procedure does not always seem to be legitimate. In translating the Hebrew parent text, the LXX translators themselves were also confronted with problematic Hebrew lexemes. Even for them, it was certainly quite a task to ascertain their precise meanings.
Ausloos, H., & Lemmelijn, B. (2016). Etymological Translations in the Septuagint. In E. Bons & J. Joosten (ed.), Die Sprache der Septuaginta – The Language of the Septuagint (p. p. 193-201). Gütersloher Verlaghaus. https://hdl.handle.net/2078.5/45897