c.1300, "transgress in some active manner, commit an aggressive offense, to sin," from Old French trespasser "pass beyond or across, cross, traverse; infringe, violate," from tres- "beyond" (from Latin trans-; see trans-) + passer "go by, pass" (see pass, v.). Meaning "enter unlawfully" is first attested in forest laws of Scottish Parliament (c.1455). The Modern French descendant of Old French trespasser, trépasser, has come to be used euphemistically for "to die" (compare euphemistic use of cross over, and obituary). Related: Trespassed; trespassing.

c.1300, "a transgression," from Old French trespas, verbal noun from trespasser (see trespass, v.). Related: Trespasses.