To trespass means to enter someone else's property without permission. If you climb over a neighbor's fence to retrieve your ball without asking first, you're trespassing. If hikers wander onto private farmland marked with “No Trespassing” signs, they're breaking the law.

Property owners have the right to control who comes onto their land. That's why you'll see trespass warnings posted around construction sites, railroad tracks, or private fields. These signs exist because entering these places without permission can be dangerous or disruptive.

The word also means violating someone's rights or boundaries in other ways. An old-fashioned prayer asks God to “forgive us our trespasses,” meaning our wrongs or offenses against others. When someone trespasses against you, they've crossed a line or violated your trust.

Trespassing carries consequences: property owners can ask trespassers to leave, and police can issue fines or make arrests for repeated violations.