1. disallow To prohibit is to give some formal command against, and especially to make some authoritative legal enactment against. Debar is said of persons, disallow of acts; one is debarred from anythin Synonyms: prohibit, debar, forbid, inhibit, preclude, disallow, hinder, interdict, prevent Antonyms: allow, empower, let, require, authorize, enjoin, license, sanction, command, give consent, order, suffer, consent to, give leave, permit, tolerate, direct, give permission, put up with, warrant