INVAL'IDATE, verb transitive [from invalid.] 1. To weaken or lessen the force of; more generally, to destroy the strength or validity of; to render of no force or effect; as, to invalidate an agreement or a contract. 2. To overthrow; to prove to be of no force; as, to invalidate an argument.
Source: Webster's 1828 American Dictionary ↗ · public-domain · returned verbatim, no AI