confirm

Synonyms: affirm approve attest authenticate back bear out bless buy certify check check out circumstantiate corroborate debunk double-check endorse establish explain give green light give high sign give stamp of approval give the goahead give the nod justify lap up make good make sure okay rubber-stamp sanction settle sign sign off on size up subscribe substantiate support thumbs up underpin uphold verify vouch warrant witness

Antonyms: annul cancel contradict destroy disprove invalidate oppose veto void

Synonyms: assure buttress clinch establish fix fortify invigorate make firm settle strengthen

Antonyms: contradict deny destroy oppose repudiate void