term:

Encroach

encroach vi

[Anglo-French encrocher, probably alteration of acrocher to catch hold of, seize, usurp, from Old French, from a-, prefix stressing goal + croc hook]
: to enter esp. gradually or stealthily into the possessions or rights of another [es on an adjoining property]

Source: Merriam-Webster's Dictionary of Law ©1996. Merriam-Webster, Incorporated. Published under license with Merriam-Webster, Incorporated.