Proposal

google

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Middle English: from Old French proposer, from Latin proponere (see proponent), but influenced by Latin propositus ‘put or set forth’ and Old French poser ‘to place’.

wiktionary

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propose +‎  -al

etymonline

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proposal (n.)

"a plan or scheme offered for acceptance," 1650s, from propose + -al (2); specific sense of "offer of marriage" is by 1749.