1. Prohibited by law.
2. Prohibited by official rules: an illegal pass in football.
3. Unacceptable to or not performable by a computer: an illegal operation.
A person who is not legally authorized to live and work in a country.
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2018 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
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