What made you want to look up xenial? Please tell us where you read or heard it (including the quote, if possible).
Black dog is an oft-used phrase to mean depression. Here's a link that attributes the phrase to Winston Churchill, but I suspect he didn't invent it. I like the way they described it though: Black Dog was Churchill's name for his depression, and as is true with all metaphors, it speaks volumes.
Here are eight ways to keep the black dog at bay after you turn back the clocks.â I checked definition of âkeep the black dog at bayâ on several online dictionaries. None of Cambridge, Oxford, Merriam-Webster, and even Urban dictionary registers this phrase. What does keep the black dog at bay mean? Keep something or somebody at bay means to prevent something or someone unpleasant from coming too near you or harming you. Black dog means a bad mood, characterized by anger, depression, or a mixture of the two.