estop (v.)

in law, "to bar, prevent, preclude," 1530s, from Anglo-French estopper "to stop, bar, hinder" (especially in a legal sense, by one's own prior act or declaration), from Old French estoper "plug, stop up, block; prevent, halt" (also in obscene usage), from estope "tow, oakum," from Latin stuppa "tow" (used as a plug); see stop (v.).