means To enter someone's land or property without permission, or more broadly to overstep a moral or legal boundary.

from From Old French 'trespasser,' to pass beyond or across, built from 'tres-' (across, from Latin 'trans') plus 'passer' (to pass). The literal sense was simply 'to cross over'—and that crossing-over is the whole idea: you've gone past where you were allowed. The same root gives the gentler old English sense in 'forgive us our trespasses,' where the boundary crossed is moral rather than a fence line.