Kenneth G. Wilson (1923–). The Columbia Guide to Standard American English. 1993.
proposal, proposition (nn.)
Both are suggestions or offers of some sort, as in He made us a proposal [proposition] that I thought was very reasonable. Proposition, like business, affair, situation, and concern, is used loosely to mean “a matter of some sort” or almost any “concern” or vague “thing”: This looks like a tough proposition (whatever this may be). Each word also has a specialized meaning concerning the relationships of man and woman: a proposal is an offer of marriage; a proposition is an invitation to have sexual intercourse outside the marital bond. Proposition in this sense is also a verb, meaning “to make such an invitation”; the verb in that sense is possibly Standard but certainly appropriate at the Conversational, Informal, and Semiformal levels.
