reject vs pass up

reject is a noun but pass up is not a noun.

Word	Noun	Adjective	Verb	Adverb
reject	Yes	No	Yes	No
pass up	No	No	Yes	No

As verbs, reject and pass up are synonyms defined as:

Other synonyms of reject include decline, refuse, turn down.

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

reject (verb)	pass up (verb)
not accept something given or offered	fail to acknowledge
dismiss from consideration or a contest	not accept as true
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