worsen

v. get worse, deteriorate; make worse, aggravate, exacerbate

Verb
1. grow worse; "Conditions in the slum worsened"
(synonym) decline
(antonym) better, improve, ameliorate, meliorate
(hypernym) change state, turn
(hyponym) inflame
(derivation) deterioration, decline in quality, declension, worsening
2. make worse; "This drug aggravates the pain"
(synonym) aggravate, exacerbate, exasperate
(antonym) better, improve, amend, ameliorate, meliorate
(hypernym) change, alter, modify
(hyponym) irritate
(derivation) worsening

(v. t.)
To make worse; to deteriorate; to impair.
  

(v. t.)
To get the better of; to worst.
  

(v. i.)
To grow or become worse.
  

      owners

Synonyms and related words:
accommodate, adapt, adjust, agent provocateur, aggravate, alter, ameliorate, amplify, annoy, augment, be changed, be converted into, be renewed, better, blast, blight, bottom out, break, break up, build up, change, checker, chop, chop and change, come about, come around, come round, convert, corrupt, damage, debase, decline, deepen, deform, degenerate, degrade, denature, descend, deteriorate, deviate, dilapidate, disimprove, disintegrate, diverge, diversify, embitter, endamage, enhance, enlarge, exacerbate, exasperate, fall back, fit, flop, foul, get worse, grow worse, harm, haul around, heat up, heighten, hot up, humble, hurt, impair, improve, increase, injure, intensify, irritate, jibe, let down, lower, magnify, make acute, make worse, meliorate, mitigate, modify, modulate, mutate, overthrow, provoke, put back, qualify, re-create, realign, rebuild, reconstruct, redesign, refit, reform, regress, relapse, remake, renew, reshape, restructure, retrograde, retrogress, revamp, revive, ring the changes, rot, sharpen, shift, shift the scene, shuffle the cards, sicken, sink, slacken, slip back, sour, subvert, swerve, tack, taint, take a turn, turn, turn aside, turn into, turn the corner, turn the scale, turn the tables, turn the tide, turn upside down, undergo a change, vary, veer, warp, weaken, work a change