What is the meaning of Loophole?

A slit in a castle wall; today, any similar window for shooting a ranged weapon or letting in light. Also written loop hole.

A method of escape, especially an ambiguity or exception in a rule or law that can be exploited in order to avoid its effect.

To prepare a building for defense by preparing slits or holes through which to fire on attackers

To exploit (a law, etc.) by means of loopholes.

Source: wiktionary.org