1To drive (a fox) from its earth.
Frequently (and in earliest use) in figurative contexts.
2To release (a dog or pack of dogs) from a kennel or other place of confinement, especially in order to pursue a fox or other quarry. Frequently (and in earliest use) figurative and in figurative contexts: to let loose.
Mid 16th century; earliest use found in Thomas Dorman (c1534–c1577), religious controversialist. From un- + kennel.