Unfair dismissal means that someone has been fired from their job in a way that is not right or fair. It is like playing a game with your friends and suddenly one friend decides to change the rules without telling everyone. This means that someone might lose unfairly because they didn't know the new rules.
Similarly, in a job, there are rules that employers and employees must follow. If an employer breaks these rules, they might fire someone in a way that is not fair. For example, if they fire someone because of their race or religion, or if they fire someone without any warning or valid reason. This would be an unfair dismissal.
If someone thinks they have been unfairly dismissed, they can talk to their employer and try to find a solution. If they cannot find a solution, they can go to a special person or organization called a tribunal, who can listen to both sides of the story and make a decision about whether the dismissal was fair or not.
In summary, unfair dismissal means being fired from a job in a way that is not fair or right. This can happen when an employer breaks the rules, and if it does happen, there are steps someone can take to try and make things right.