down in the mouth是什么意思

"gloomy at the thought of what he had to face" "gloomy predictions" "a gloomy silence" "took a grim view of the economy" "the darkening mood" "lonely and blue in a strange city" "depressed by the loss of his job" "a dispirited and resigned expression on her face" "downcast after his defeat" "feeling discouraged and downhearted"