Entry 1 sense Webster, 1913 Atrabilious · At·ra·bil·ious · IPA /ˌæ.tɹəˈbɪl.i.əs/ 01 a. Melancholic or hypochondriac; atrabiliary. 1. Melancholic or hypochondriac; atrabiliary. “A hard-faced, atrabilious, earnest-eyed race.” — Lowell. “He was constitutionally atrabilious and scornful.” — Froude.