Synonyms and related words :
accelerate, accrue, accumulate, add to, advance, affirm, aggravate, animate, anneal, appreciate, attest, augment, authenticate, back, back up, balloon, be tough, bear out, beef up, bloat, blow up, bolster, boom, boost, brace, brace up, breed, broaden, buttress, case harden, certify, cheer, chirk up, circumstantiate, complicate, concentrate, condense, confirm, consolidate, corroborate, crescendo, deepen, develop, document, double, embolden, encourage, endure, energize, enhance, exacerbate, exaggerate, fortify, gain, gain strength, gelt, get ahead, gird, go up, grow, hang tough, harden, hearten, heat up, heighten, hop up, hot up, increase, inspirit, intensify, invigorate, jazz up, key up, magnify, make complex, mount, multiply, nerve, nourish, nutrify, prepare, probate, proliferate, prop, prove, ramify, ratify, ready, recruit, redouble, refresh, reinforce, reinvigorate, rejuvenate, renew, restrengthen, rigidify, rise, run up, screw up, sharpen, shoot up, shore up, sinew, snowball, soup up, spread, steel, step up, stiffen, substantiate, supplement, support, sustain, swell, temper, tense, tighten, tone up, toughen, trice up, triple, undergird, uphold, validate, verify, vitalize, warrant, wax, whet, widen