Ultra vires
Ultra vires ('beyond the powers') is a Latin phrase used in law to describe an act that requires legal authority but is done without it. Its opposite, an act done under proper authority, is intra vires ('within the powers'). Acts that are intra vires may equivalently be termed "valid", and those that are ultra vires termed "invalid". Legal issues relating to ultra vires can arise in a variety of contexts:

Companies and other legal persons sometimes have limited legal capacity to act, and attempts to engage in activities beyond their legal capacities may be ultra vires. Most countries have restricted the doctrine of ultra vires in relation to companies by statute.