black dog

noun Informal.

melancholy; despondency; the blues: The black dog is over him.

Origin of black dog

First recorded in 1700–10

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

British Dictionary definitions for black dog

black dog

noun

informal depression or melancholy

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012