11 letters · 13 points in Scrabble
adjective irritable as if suffering from indigestion
originFrom Latin ātra bīlis (“black bile”) (āter (“dark, black”) + bīlis (“bile”)) + -ous (“full of”), referring to the humour which ancient Hippocratic and later Galenic medicine associated with sadness and despondency.
Etymology from Wiktionary, CC BY-SA 3.0