A more thorough explanation:

Definition: The subject of an action refers to the right or property that is being disputed in a lawsuit. It is the basis of a legal claim.

Example: In a divorce case, the subject of the action may be the division of property and assets between the two parties. Each party may claim ownership of certain assets, such as a house or a car, and the court will determine who has the legal right to those assets.

Another example: In a personal injury case, the subject of the action may be the compensation that the injured party is seeking for their medical expenses, lost wages, and pain and suffering. The injured party is making a legal claim against the party responsible for their injuries.

These examples illustrate how the subject of an action is the main issue that is being disputed in a legal case. It is the reason why the case is being brought to court, and the outcome of the case will depend on the resolution of this issue.