Synonyms and related words :
affirm, attest, attested copy, authenticate, back, back up, bear out, bequeathal, bequest, bolster, buttress, certify, circumstantiate, codicil, confirm, corroborate, devise, document, fortify, inheritance, legacy, prove, ratify, reinforce, strengthen, substantiate, support, sustain, testament, undergird, uphold, validate, verify, warrant, will