Antonyms for the phrase "hold in custody" include release, free, liberate, discharge, emancipate, and let go. When someone is not held in custody, they are free to move and act as they please without any restriction. To release someone from custody means to set them free or permit them to leave custody. Moreover, to free someone implies that they are unbound from whatever was holding them in custody. In contrast, holding someone in custody suggests that they are confined or restrained against their will. These antonyms serve as opposing concepts that convey the absence or presence of restraint, confinement, and freedom.