nullipotent

Etymology
roots, – literally, “having no power”.

Adjective

 * 1)  Describing an action which has no side effect. Queries are typically nullipotent: they return useful data, but do not change the data structure queried. Contrast with idempotent.
 * 2)  Incapable of developing into any cell type; compare pluripotent

Usage notes
In computing, contrast with : both refer to the potential result of performing an action on an object multiple times, the difference being that an idempotent action's result would be the same as performing it one time, while the nullipotent action's result would be the same as performing it zero times.

In other words, a nullipotent action has no side effects – performing it multiple times is the same as performing it zero times. An idempotent action has no further side effects after the first time performing it – performing it multiple times is the same as performing it one time.