Synonyms for Sustain:

n.

abandon, align, ally, drop, get behind, pack, promote, sympathize, tote, transfer, agree with, speak up for. allow, appeal, appear, arraign, call, cite, injure, neglect, provide, bring before. befriend, bring about, catalyze, comfort, create, form, hinder, inaugurate, invent, start-off, trigger, set off, stand by, side with, stand up for. embolden, hearten, uplift, build up someone's hopes, raise (someone's) hopes/expectations. go through, come under, be in dire/desperate straits, be in the grip of something, not know where/which way to turn. sustain (noun)
affirm, confirm, corroborate, get, have, hold, hold up, keep, keep up, maintain, nourish, nurture, prolong, substantiate, suffer, support.

v.

affirm (verb)
accept, acknowledge, adjure, admit, affirm, approve, assert, assure, attest, aver, avouch, certify, claim, contend, corroborate, declare, endorse, express, pledge, proclaim, profess, promise, pronounce, propound, ratify, set down, state, submit, testify, validate, verify, warrant.
aid (verb)
abet, aid, assist, attend, benefit, encourage, endow, facilitate, foster, fund, help, minister, mother, motivate, relieve, serve, support, tend.
assist (verb)
avail, back, favor, succor, uphold.
continue (verb)
abide, continue, extend, maintain, persevere, persist, prolong, protract.
defend (verb)
answer, argue, avert, backfire, bar, barricade, buffer, counter, counterattack, cover, defend, fend, guard, oppose, police, protect, rebut, reply, resist, respond, retort, return, safeguard, save, screen, secure, shelter, shield, ward.
endure, experience (verb)
abide, have, suffer.
feed (verb)
fatten, feed, nourish, nurse, nurture, suckle, wine and dine, breast-feed, cater to.
keep up, maintain (verb)
aid, approve, assist, back, befriend, comfort, confirm, continue, defend, endorse, favor, feed, foster, help, nourish, nurse, nurture, pack, prolong, protract, ratify, relieve, save, support, tote, transfer, uphold, validate, verify, stand by.
stative (verb)
keep up, prolong.

Other synonyms:

embolden, hearten. uplift. assist
facilitate, stand up for.
back
side with.
carry
tote.
defend
speak up for.
energize
trigger.
protect
defend.
support
back, support.
Other relevant words:
abandon, align, allow, ally, appeal, appear, arraign, befriend, call, catalyze, cite, comfort, confirm, create, drop, embolden, form, get, go through, have, hearten, hinder, hold, hold up, inaugurate, injure, invent, keep, keep up, neglect, pack, promote, provide, substantiate, suffer, sympathize, tote, transfer, trigger, uplift, agree with, stand up for, speak up for.

Usage examples for sustain

  1. Be faithful, and more than earthly fortune is thine; for I say unto thee, I shall not fail, having grace to sustain this combat. – The Short Works of George Meredith by George Meredith Last Updated: March 7, 2009
  2. I had besides lost other things that used to sustain me, and being reckless, I was contemptuous, and listened to the talk about money with sublime indifference to the subject: with an attitude, too, I daresay. – The Adventures of Harry Richmond, Complete by George Meredith Last Updated: March 7, 2009
  3. And she did sustain herself. – Orley Farm by Anthony Trollope