List of undergird synonyms and undergird related words.
affirm, afford support, attest, authenticate, back, back up, bear, bear out, bear up, bed on, beef up, bolster, bolster up, bottom on, brace, brace up, build on, buoy up, buttress, carry, case harden, certify, circumstantiate, confirm, corroborate, cradle, crutch, cushion, document, finance, fortify, found on, fund, gird, give support, ground on, harden, hold, hold up, invigorate, keep, keep afloat, keep up, lend support, mainstay, maintain, nerve, pillow, probate, prop, prop up, prove, ratify, refresh, reinforce, reinvigorate, restrengthen, set on, shore, shore up, shoulder, stay, steel, stiffen, strengthen, subsidize, substantiate, subvention, subventionize, support, sustain, temper, toughen, underbrace, underlie, underpin, underset, upbear, uphold, upkeep, validate, verify, warrant