turn down vs reject

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

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

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

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

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

Other synonyms of turn down include decline, pass up, refuse.

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

Other synonyms of turn down include refuse, turn away.

turn down (noun)	reject (noun)
	the person or thing that is rejected or set aside as inferior in quality

turn down (verb)	reject (verb)
make lower or quieter	not accept something given or offered
take a downward direction	dismiss from consideration or a contest
reject with contempt	deem wrong or inappropriate
not accept as true	reject with contempt
refuse entrance or membership	not accept as true
	refuse entrance or membership
	resist immunologically the introduction of some foreign tissue or organ