To violate means to break a rule, law, or agreement, or to treat something sacred or important with disrespect. When a basketball player violates the rules by taking too many steps without dribbling, the referee calls a violation and gives the ball to the other team. When someone violates a promise, they break their word and don't do what they said they would do.

The word carries a sense of crossing an important boundary. You might violate school rules by running in the hallway, or violate traffic laws by speeding. Countries can violate treaties they've signed with other nations. The word suggests that something meant to be protected or respected has been damaged or disregarded.

Violate can also mean invading someone's privacy or personal space in a way that makes them feel unsafe or disrespected. Reading someone's private diary without permission violates their privacy. The word is stronger than just “break” because it implies that what was broken mattered and should have been protected.

A violation is the act of violating something, and a violator is someone who commits a violation. When you see a “No Trespassing” sign, it's warning you not to violate someone's property rights by entering without permission.