1. gloomy, melancholy, or ill-tempered; prone to depression or irritability
Usage: formal or literary; derived from the medieval medical theory of black bile (atrabilis) as a cause of melancholy

Examples

• The atrabilious old professor complained bitterly about every aspect of university life.
• Her atrabilious disposition made her difficult to work with on group projects.
• He had an atrabilious temperament that worsened during the long winter months.
• The character's atrabilious nature was evident in his cynical remarks about human nature.
• Despite her atrabilious outlook, she occasionally showed flashes of dry humor.
• His atrabilious mood lifted slightly when his friend brought good news.