A more thorough explanation:

Definition: A stickler is a person who acts as an arbitrator, someone who settles disputes or disagreements between two parties.

Example: In medieval times, a stickler was a person who ensured that the rules of a jousting tournament were followed. They would make sure that the knights followed the rules and that there was no cheating.

Explanation: The example illustrates how a stickler acted as an arbitrator in a specific situation. They were responsible for ensuring that the rules were followed and that there was fair play. In modern times, a stickler can be someone who settles disputes in any field, such as a mediator in a legal case or a negotiator in a business deal.