What is Fugitive Offenders?

Legal Definition
In English law. Where a person accused of any offence punishable by imprisonment, with hard labor for twelve months or more, has left that part of his majesty's dominions where the offence is alleged to have been committed, he is liable, if found in any other part of his majesty's dominions, to be apprehended and returned in manner provided by the fugitive offenders' act, 1881, to the part from which he is a fugitive. Wharton.
-- Black's Law Dictionary