affirm, afford support, attest, authenticate, back, back up, bear, bear up, bolster, bolster up, buttress, certify, circumstantiate, confirm, corroborate, crutch, document, finance, fortify, fund, give support, hold up, justify, keep, lend support, maintain, probate, prop, prop up, prove, ratify, reinforce, shore, shore up, strengthen, subsidize, substantiate, subvention, subventionize, support, sustain, undergird, upbear, uphold, upkeep, validate, verify, warrant