Support with evidence or authority or make more certain or confirm.

synonyms: corroborate, support, underpin.

Roget 467: be evidence etc. n.; evince, show, betoken, tell of; indicate etc. (denote) 550; imply, involve, argue, bespeak, breathe.    have weight, carry weight; tell, speak volumes; speak for itself etc. (manifest) 525.    rest upon, depend upon; repose on.    bear witness etc. n.; give evidence etc. n.; testify, depose, witness, vouch for; sign, seal, undersign^†, set one's hand and seal, sign and seal, deliver as one's act and deed, certify, attest; acknowledge etc. (assent) 488.    [provide conclusive evidence] make absolute, confirm, prove (demonstrate) 478.    [add further evidence] indorse, countersign, corroborate, support, ratify, bear out, uphold, warrant.    adduce, attest, cite, quote; refer to, appeal to; call, call to witness; bring forward, bring into court; allege, plead; produce witnesses, confront witnesses.    place into evidence, mark into evidence.    [obtain evidence] collect evidence, bring together evidence, rake up evidence; experiment etc. 463.    have a case, make out a case; establish, authenticate, substantiate, verify, make good, quote chapter and verse; bring home to, bring to book.    ... show more

Dutch: onderbouwen