Perhaps a compound of לִוְיָה (livyá, “garland, wreath”) + -תָּן (-tan, agentive suffix), meaning “the tortuous one”; in any case likely related to the root Hebrew לוה (“wind, turn, twist”). Likely also related to Ugaritic 𐎍𐎚𐎐 (ltn).
לווייתן / לִוְיָתָן • (livyatán) m (plural indefinite לווייתנים \ לִוְיָתָנִים)