give high sign

affirm approve back certify corroborate endorse establish explain sign substantiate support uphold verify

attest authenticate bless buy check circumstantiate debunk double-check justify okay sanction settle subscribe underpin vouch warrant witness

bear out check out give green light give stamp of approval give the go-ahead give the nod lap up make good make sure rubber-stamp sign off on size up thumbs-up

confuse contradict deny disallow disapprove discredit disprove invalidate oppose refuse reject

disagree refute veto

annul cancel destroy repudiate void