ratchet down vs ratchet

ratchet down is not a noun while ratchet is a noun.

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

As verbs, ratchet down and ratchet are synonyms defined as:

Other synonyms of ratchet down include rachet up.

ratchet down (noun)	ratchet (noun)
	mechanical device consisting of a toothed wheel or rack engaged with a pawl that permits it to move in only one direction

ratchet down (verb)	ratchet (verb)
move by degrees in one direction only	move by degrees in one direction only