c.1300, "transgress, offend, sin," from Old French trespasser "pass beyond or across," from tres- "beyond" (from Latin trans-) + passer "go by, pass" (see pass (v.)). Meaning "enter unlawfully" is first attested in forest laws of Scottish Parliament (c.1455). The noun is recorded from late 13c. The modern descendant of Old French trespasser, French trépasser has come to be used euphemistically for "to die" (cf. cross over, and obituary).