turn down vs disdain

turn down is not a noun while disdain is a noun.

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

As verbs, turn down and disdain are synonyms defined as:

Other synonyms of turn down include freeze off, pooh-pooh, reject, scorn, spurn.

turn down (noun)	disdain (noun)
	a communication that indicates lack of respect by patronizing the recipient
	lack of respect accompanied by a feeling of intense dislike

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