legal
Allowed by law or related to the law.
Legal means allowed or recognized by law. When something is legal, you can do it without breaking the rules that govern society. Driving is legal once you're old enough and have a license. Starting a lemonade stand might be legal in your neighborhood, while in some places you'd need a permit first.
The opposite of legal is illegal, which means against the law. Stealing is illegal. So is driving without a license or breaking into someone's house. Laws exist to protect people and keep society running smoothly, so understanding what's legal matters in everyday life.
Legal can also describe things related to the law itself. A legal document is an official paper like a contract or a will. Legal advice comes from a lawyer who studied the law. When someone hires legal representation, they're getting a lawyer to speak for them in court.
Sometimes people confuse legal with ethical or moral, but they're different. Something can be legal but still wrong (like being cruel to a friend), and something can be right but illegal (like breaking an unjust law). Legal simply means whether the law permits it, not whether it's the best choice or the kindest action.