Answer:
A court Injunction
Step-by-step explanation:
A plaintiff is someone who institutes or starts a legal case against another person in a court of law.
A defendant is the person who has been summoned to a court of law to answer to a case instituted by a plaintiff.
An Injunction is a court order that compels a person to carry out or refrain from carrying out a specific action.
So in this question, if an agreement or a contract exists between two people and one of them does not want to fulfil his/her part of the agreement, then the aggrieved person (plaintiff) can go to a court of law to obtain an injunction that will compel the erring person (defendant) to fulfil his/her part of the contract,