Interloper Definition: A person who, without legal right, runs a business (eg. without mandatory licenses), or who wrongfully interferes or intercepts another's business. In the 1957 Supreme Court of Minnesota case, Re Bush's Trust, Justice Matson wrote:"Where a party-litigant has no financial interest or other right which could be affected either adversely or favorably by the outcome of the litigation, he is a mere interloper...."James Ballentine defined an interloper as follows:"A trader operating without a license required by law."A party who takes an appeal or participates in an appeal taken by others who has no financial interest or other right which could be affected either adversely or favorably by the outcome of the litigation."In litigation, a litigant must have a genuine interest in the matter as opposed to being an interloper, or what has been also referred to as a "mere busybody".1 For example, in Tel-Oren, these words were used by the United States Court of Appeals:"The United States would be perceived, and justly so, not as a nation magnanimously refereeing international disputes but as an officious interloper and an international busybody." REFERENCES:The Friends of the Greenspace Alliance v. Ottawa (City), 2011 ONSC 472 [NOTE 1]In re Declaration of Trust by Bush, 81 NW 2d 615 (1957)In the Matter of the Complaint of Ta Chi Navigation (Panama) Corporation, 583 F. Supp. 1322Tel-Oren v. Libyan Arab Republic, 726 F. 2d 774 (1984) Categories & Topics: Civil Litigation & Evidence Law Dictionary Find you are constantly looking up definitions? Try our search provider (works in most modern browsers) If you find an error or omission in Duhaime's Legal Dictionary, or if you have legal term suggestion, we'd love to hear from you!