Which term means to make something more acceptable by adding something else?

The term that best fits the definition of making something more acceptable by adding something else is "mollify." To mollify means to appease or pacify someone's feelings or emotions by adding a comforting or mitigating element. This can involve providing reassurance, concessions, or additional benefits that help soften a situation or make it more palatable, thus enhancing acceptability.

In contrast, to rescind means to revoke or cancel a decision or agreement, which does not fit the idea of adding anything to make a situation more acceptable. Sanction can mean both to approve or to impose penalties, depending on the context, but it does not inherently involve adding something to improve acceptability. Lastly, a parody is a humorous or satirical imitation, which does not relate to making something more acceptable in the context described.