Definition of: annul

(ə·nul′) v.t. an·nulled, an·nul·ling
1. To destroy the force of; declare void or invalid, as a law.
2. To reduce to nothing; extinguish: One loyalty may annul another in the mind.
3. To put an end or stop to, as a practice. [ < OF anuller < LL annullare < L ad- to + nullus none]
—an·nul′la·ble adjective Synonyms: abolish, abrogate, cancel, destroy, extinguish, nullify, obliterate, quash, repeal, rescind, revoke. See ABOLISH, CANCEL. Antonyms: confirm, enact, establish, institute, maintain, preserve, sustain, uphold.