Which word describes a lack of restraint or severe control?

The word "unbridled" accurately describes a lack of restraint or severe control. It conveys a sense of freedom or lack of limitations in behavior, emotion, or expression. For instance, when one talks about "unbridled enthusiasm," it indicates an exuberant and unrestricted display of excitement that isn’t held back by any social norms or boundaries.

In contrast, the other words offered do not pertain to the concept of restraint or control. To extol means to praise highly, which does not relate to control. Sanction can refer to both a penalty for disobeying a law and the approval of an action; thus, it does not imply lack of restraint. Lastly, precocity refers to the state of being advanced or mature beyond one’s age, particularly in mental or physical development, and does not address the idea of restraint or control at all. Therefore, "unbridled" is the most fitting choice to encapsulate the idea of a lack of restraint or control.