steady down vs roost

steady down is not a noun while roost is a noun.

Word	Noun	Adjective	Verb	Adverb
steady down	No	No	Yes	No
roost	Yes	No	Yes	No

As verbs, roost is a hyponym of steady down; that is, roost is a word with a more specific, narrower meaning than steady down:

steady down: become settled or established and stable in one's residence or life style
roost: settle down or stay, as if on a roost

steady down (noun)	roost (noun)
	a perch on which domestic fowl rest or sleep
	a shelter with perches for fowl or other birds

steady down (verb)	roost (verb)
become settled or established and stable in one's residence or life style	settle down or stay, as if on a roost
	sit, as on a branch