at·ra·bil·ious 
(ăt′rə-bĭlyəs) also at·ra·bil·i·ar (-bĭlē-ər)
(ăt′rə-bĭlyəs) also at·ra·bil·i·ar (-bĭlē-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 the Appendix of Indo-European roots + bīlis, bile.]
at′ra·bilious·ness n.