A0505600 (ăt′rə-bĭl′yəs) also at·ra·bil·i·ar(-bĭl′ē-ər)adj.1. Inclined to melancholy.2. Having a peevish disposition; surly.[From Latin ātra bīlis, black bile (translation of Greek melankhōliā) : ātra, black; see āter- in Indo-European roots + bīlis, bile.]at′ra·bil′ious·ness n.MedicalSeeatrabilious