Bile

Physiology. a bitter, alkaline, yellow or greenish liquid, secreted by the liver, that aids in absorption and digestion, especially of fats.
ill temper; peevishness.
Old Physiology. either of two humors associated with anger and gloominess.
Contemporary Examples

From the JetBlue Pilot to Robert Bales, Cultural Road Rage Is Everywhere Lee Siegel March 27, 2012
Jobs’s Unorthodox Treatment Sharon Begley October 5, 2011
Running the Republicans Stanley Crouch March 5, 2009
When Love Hurts John Douglas Marshall July 26, 2009
Most Comments Are Horrible—Sites Look for Ways to Make Them Better Jesse Singal July 15, 2012

Historical Examples

Catholic World, Vol. XIII, April to September, 1871 Various
Meadow Grass Alice Brown
Encyclopaedia Britannica, 11th Edition, Volume 15, Slice 3 Various
Timaeus Plato
American Red Cross Text-Book on Home Hygiene and Care of the Sick Jane A. Delano

noun
a bitter greenish to golden brown alkaline fluid secreted by the liver and stored in the gall bladder. It is discharged during digestion into the duodenum, where it aids the emulsification and absorption of fats
irritability or peevishness
(archaic) either of two bodily humours, one of which (black bile) was thought to cause melancholy and the other (yellow bile) anger
verb
a Scot word for boil1
n.

bile
(bīl)
A bitter, alkaline, brownish-yellow or greenish-yellow fluid that is secreted by the liver, concentrated and stored in the gallbladder, and discharged into the duodenum of the small intestine. It helps in the digestion of fats and the neutralization of acids, such as the hydrochloric acid secreted by the stomach. Bile consists of salts, acids, cholesterol, lipids, pigments, and water. ◇ Bile salts help in the emulsification, digestion, and absorption of fats. ◇ Bile pigments are waste products formed by the breakdown of hemoglobin from old red blood cells.

Note: Bile is sometimes used figuratively to denote bitterness in general: “His writing was full of bile.”