low-spirited vs down in the mouth

low-spirited and down in the mouth both are adjectives.

Word	Noun	Adjective	Verb	Adverb
low-spirited	No	Yes	No	No
down in the mouth	No	Yes	No	No

As adjectives, low-spirited and down in the mouth are synonyms defined as:

low-spirited and down in the mouth: filled with melancholy and despondency

Other synonyms of low-spirited include blue, depressed, dispirited, down, downcast, downhearted, gloomy, grim, low.

low-spirited (adjective)	down in the mouth (adjective)
filled with melancholy and despondency	filled with melancholy and despondency