What is "prescriptivity"

n. The quality or state of being prescriptive.

Prescriptivity is a term used in meta-ethics to state that when an evaluative judgment or decision is made it must either proscribe or condemn. The word implies that these judgments (and the prescription and condemnation) logically commit us to certain ways of living. Contrary to popular opinion prescriptivity does not just describe or categorize decisions for example; "You ought to do this" (used evaluatively) logically entails the imperative "Do this."