Rule nisi pronounced rule ni (as in night) si ( as in sight) means a rule which will become fully authoritative and binding on a party unless, on a notice to show cause why the rule should not be made final, the party comes to and satisfies the Court

Nisi is Latin for "unless." A judgment nisi is an intermediate judgment which will become final unless a party appeals or formally requests the court to set it aside. This word is frequently used in legal proceedings to denote that something has been done, which is to be valid unless something else shall be done within a certain time to defeat it.

In Delhi Administration v Gurdip Singh Uban, - 2000 SOL Case No. 473, the Supreme Court of ndia explained what the rule means,

The words `rule nisi' and `rule absolute' are words frequently used by the High Court every day in the writ jurisdiction. As stated in Ramanatha Iyer's Law Lexicon (p. 1698, 2nd Ed., Reprint, 2000) : `Rule absolute' means `a rule to show cause upon which, on hearing, the Court has made a peremptory order, that the party shall do as the rule requires.' A Court may issue rule nisi initially which is in the nature of a show cause. After hearing, the Court may discharge the rule if it is inclined to reject the writ petition. If, on the other, the rule is made absolute, the Court order is a direction for the performance of the act forthwith.

“For whoever keeps the whole law but fails in one point has become guilty of all of it." James 2:10 Bible