Legal Definition of Mitigate: To lessen, as in reducing the punishment of a convicted person or decreasing the amount of damages a plaintiff may have been awarded. Also, to reduce the charges, such as from first-degree murder to manslaughter, because of extenuating circumstances | Looking to understand the legal definition of mitigate? Learn how mitigation can lessen punishment or damages awarded to a plaintiff and reduce charges. Explore examples and discover the importance of mitigation for business owners