I know "propsal" may have different meanings. Then in the following sentence "She refused his proposal." Will there be misunderstanding? That is, is it likely for people to interprete "proposal" as suggestion instead of "offer of marriage"? Looking forward to your help.
The word more frequently substituted for "suggestion" is "proposition", so I don't think there would be much misunderstanding. Of course "proposal" is short for "proposal of marriage", but if I read "she refused/turned down his proposal", my first thought would be "offer of marriage".
Context would, of course, help. If the rest of the paragraph had been about a man going to his female boss with a business proposal, then the meaning would be clear. If it had been about a romantic relationship, then it would be a reasonable assumption that it was about a marriage proposal.