Main Entry: in·val·i·date

Pronunciation: \(ˌ)in-ˈva-lə-ˌdāt\

Function: transitive verb

Date: 1649

: to make invalid; especially : to weaken or destroy the cogency of

synonyms see nullify

— in·val·i·da·tion \-ˌva-lə-ˈdā-shən\ noun

— in·val·i·da·tor \in-ˈva-lə-ˌdā-tər\ noun