turndown vs turn down

turndown is a noun but turn down is not a noun.

Word	Noun	Adjective	Verb	Adverb
turndown	Yes	No	No	No
turn down	No	No	Yes	No

turndown (noun)	turn down (noun)
the act of refusing an offer

turndown (verb)	turn down (verb)
	make lower or quieter
	take a downward direction
	reject with contempt
	not accept as true
	refuse entrance or membership