It is a Latin word that means No one; no man. It is also the initial word of many Latin phrases and maxims, among which is Nemo agit in seipsum meaning No man acts against himself or ‘Nemo dat quod non habet’ means ‘no one can give what they do not have’. This rule is commonly referred to as the Nemo Dat Rule. Nemo Dat is the legal principle that a person who does not have adequate ownership of goods or property cannot transfer the ownership of those goods or that property to someone else.
This principle can be explained through the following example. Suppose, X transfers his property to Y. Then X turns around and transfers the property to Z. Following the rule of nemo dat quod non habet, Y will get the right from X. Now Y have the rights and X have none. So X cannot transfer Z the property. The rule of nemo dat has its base as a chain of transactions. The current owner should be able to trace his rights back in time to prove his legitimate acquisition.
Nemo debet bis vexari translates as “No one should be tried twice in respect to the same matter.”If a man is indicted again for the same offence in an English court, he can plead, as a complete defense, his former acquittal or conviction.This principle has been recognized and adopted by the Indian Legislature and is embodied in the provisions of Section 26 of the General Clauses Act and Section 403 of the Criminal Procedure Code. You may refer the case of S.A. Venkataraman v. Union of India, 1954 for understanding this maxim.