black bile

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun One of the four humors of ancient and medieval physiology, supposed to cause melancholy when present in excess.

from The Century Dictionary.

• noun See atrabile.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun One of the four humours of ancient and mediaeval physiology, that was believed to be secreted by the kidneys and spleen and to cause melancholy and sadness when present in excess.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun a humor that was once believed to be secreted by the kidneys or spleen and to cause sadness and melancholy