down vs depressed

down is a noun but depressed is not a noun.

Word	Noun	Adjective	Verb	Adverb
down	Yes	Yes	Yes	Yes
depressed	No	Yes	No	No

As adjectives, down and depressed are synonyms defined as:

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

As adjectives, down and depressed are synonyms defined as:

down (noun)	depressed (noun)
(American football) a complete play to advance the football
soft fine feathers
fine soft dense hair (as the fine short hair of cattle or deer or the wool of sheep or the undercoat of certain dogs)
(usually plural) a rolling treeless highland with little soil

down (adjective)	depressed (adjective)
being or moving lower in position or less in some value	filled with melancholy and despondency
filled with melancholy and despondency	lower than previously
extending or moving from a higher to a lower place	flattened downward as if pressed from above or flattened along the dorsal and ventral surfaces
becoming progressively lower
not functioning (temporarily or permanently)
lower than previously
shut
being put out in a game of baseball
understood perfectly

down (verb)	depressed (verb)
improve or perfect by pruning or polishing
bring down or defeat (an opponent)
drink down entirely
eat up completely, as with great appetite
cause to come or go down
shoot at and force to come down

down (adverb)	depressed (adverb)
spatially or metaphorically from a higher to a lower level or position
away from a more central or a more northerly place
paid in cash at time of purchase
in an inactive or inoperative state
to a lower intensity
from an earlier time