rule out vs reject

rule out is not a noun while reject is a noun.

Word	Noun	Adjective	Verb	Adverb
rule out	No	No	Yes	No
reject	Yes	No	Yes	No

As verbs, rule out and reject are synonyms defined as:

Other synonyms of rule out include eliminate, winnow out.

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

rule out (verb)	reject (verb)
dismiss from consideration or a contest	not accept something given or offered
include or exclude by determining judicially or in agreement with rules	dismiss from consideration or a contest
make impossible, especially beforehand	deem wrong or inappropriate
	reject with contempt
	not accept as true
	refuse entrance or membership
	resist immunologically the introduction of some foreign tissue or organ