- The definition of an isolationist is a person who believes in keeping to one's own affairs rather than becoming involved in the affairs of others.
A person who believes that the United States should mind its own business and not interfere with things going on in other countries is an example of an isolationist.
(comparative more isolationist, superlative most isolationist)
- Of or pertaining to isolationism or an advocate thereof.
- One who advocates or supports isolationism.