1. to act in such a way as to cause an offense to seem less serious
2. a partial excuse to mitigate censure; an attempt to represent an offense as less serious than it appears by showing mitigating circumstances
3. the action of lessening in severity or intensity
the object being control or moderation of economic depressions
4. The act of mitigating, or the state of being mitigated; abatement or diminution of anything painful, harsh, severe, afflictive, or calamitous; as, the mitigation of pain, grief, rigor, severity, punishment, or penalty.