Invade in great numbers:
— The roaches infested our kitchen.

synonym: overrun.

Roget 830: cause pain, occasion pain, give pain, bring pain, induce pain, produce pain, create pain, inflict pain etc. 828; pain, hurt, wound.    pinch, prick, gripe etc. (physical pain) 378; pierce, lancinate^†, cut.    hurt the feelings, wound the feelings, grate upon the feelings, grate upon the nerves, jar upon the feelings; wring the heart, pierce the heart, lacerate the heart, break the heart, rend the heart; make the heart bleed; tear the heart strings, rend the heart strings; draw tears from the eyes.    sadden; make unhappy etc. 828; plunge into sorrow, grieve, fash^†, afflict, distress; cut up, cut to the heart.    displease, annoy, incommode, discompose, trouble, disquiet; faze, feaze^†, feeze [U.S.]; disturb, cross, perplex, molest, tease, tire, irk, vex, mortify, wherret^†, worry, plague, bother, pester, bore, pother, harass, harry, badger, heckle, bait, beset, infest, persecute, importune.    wring, harrow, torment, torture; bullyrag; put to the rack, put to the question; break on the wheel, rack, scarify; cruciate^†, crucify; convulse, agonize; barb the dart; plant a dagger in the breast, plant a thorn in one's side.    irritate, provoke, sting, nettle, try the patience, pique, fret, rile, tweak the nose, chafe, gall; sting to the quick, wound to the quick, cut to the quick; aggrieve, affront, enchafe^†, enrage, ruffle, sour the temper; give offense etc. (resentment) 900.    maltreat, bite, snap at, assail; smite etc. (punish) 972.    sicken, disgust, revolt, nauseate, disenchant, repel, offend, shock, stink in the nostrils; go against the stomach, turn the stomach; make one sick, set the teeth on edge, go against the grain, grate on the ear; stick in one's throat, stick in one's gizzard; rankle, gnaw, corrode, horrify, appal^†, appall, freeze the blood; make the flesh creep, make the hair stand on end; make the blood curdle, make the blood run cold; make one shudder.    haunt the memory; weigh on the heart, prey on the heart, weigh on the mind, prey on the mind, weigh on the spirits, prey on the spirits; bring one's gray hairs with sorrow to the bring one's gray hairs with sorrow to the grave; add a nail to one's coffin.    ... show more

Occupy in large numbers or live on a host:
— The Kudzu plant infests much of the South and is spreading to the North.

synonyms: invade, overrun.

Live on or in a host, as of parasites.