proposal vs marriage offer

proposal and marriage offer both are nouns.

Word	Noun	Adjective	Verb	Adverb
proposal	Yes	No	No	No
marriage offer	Yes	No	No	No

As nouns, proposal and marriage offer are synonyms defined as:

Other synonyms of proposal include marriage proposal, proposal of marriage.

proposal (noun)	marriage offer (noun)
something proposed (such as a plan or assumption)	an offer of marriage
the act of making a proposal
an offer of marriage