1. nullify Abolish, to do away with, bring absolutely to an end, especially as something hostile, hindering, or harmful, was formerly used of persons and material objects, a usage now obsolete except in poetr Synonyms: abolish, abate, eradicate, prohibit, stamp out, abrogate, exterminate, remove, subvert, annihilate, extirpate, repeal, supplant, annul, nullify, reverse, suppress, destroy, obliterate, revoke, terminate, end, overthrow, set aside Antonyms: authorize, establish, reinstate, revive, cherish, institute, renew, set up, confirm, introduce, repair, support, continue, legalize, restore, sustain, enact, promote