Indecent proposal is a phrase that typically refers to an offer, proposition, or suggestion that is considered inappropriate, immoral, or offensive. There are several alternatives for the term that one can use depending on the situation. For instance, some may use "immoral proposition," "shameful offer," or "disgraceful proposal." Others might opt for "improper suggestion," "unacceptable bribe," or "morally objectionable proposal." Whatever phrase is used, it often implies that the proposal goes beyond what is considered socially acceptable or ethically sound. Therefore, it is important to use the appropriate term for the given context to avoid misunderstanding.