Definition of Trespasser
A trespasser is a person who goes onto another person's property without permission. Premise liability law may distinguish between persons who are on the property legally such as licensees, social guests and invitees and those who are on the property illegally such as the trespasser.
If a person is an invitee or a licensee the owner of the property is expected to exercise reasonable care for their safety. If the person is a trespasser the owner also may be required to give reasonable warning to prevent injury, especially if they have created an "artificial condition." If someone has been injured are your property and they were trespassing it is important to talk to an injury lawyer about the premise liability laws in your state.