officious intermeddler (<<schwa>>-fish-<<schwa>>s). A person who confers a benefit on another without being requested or having a legal duty to do so, and who therefore has no legal grounds to demand restitution for the benefit conferred. — Sometimes shortened to intermeddler.

[Cases: Implied and Constructive Contracts 3. C.J.S. Implied and Constructive Contracts § 5.]

[Blacks Law 8th]