I have been searching online for a particular word; that approximates to an antonym of ameliorate. I am after a specific word.

ameliorate verb

to make better
Synonyms ameliorate, amend, better, enhance, enrich, help, meliorate, perfect, refine, upgrade
Related Words correct, emend, rectify, reform, remediate, remedy; edit, fine-tune, redraft, refurbish, rehab, rehabilitate, revamp, revise, rework; beef (up), boost, fortify, intensify, reinforce (also reenforce), strengthen; fine, hone, polish; retouch, touch up
Near Antonyms damage, endamage, harm, hurt, impair, injure, spoil, tarnish, vitiate; blemish, blight, deface, disfigure, flaw, mar; diminish, lessen, lower, reduce
Antonyms worsen

The word is eluding me... it sounds like detiliorate.. not deteriorate. My example is, probably, misleading, as my searches on google are not throwing up any alternative words.. So I'm probably way off base.

Anyone know the word I am trying to remember?

  • 1
    Deteriorate is usually intransitive, but the transitive meaning ("To make worse or of inferior quality; to lower in character or excellence; to worsen.") is older, and I certainly use it occasionally.
    – Colin Fine
    Sep 15, 2013 at 11:42
  • The lation melior (better) is the comparative of bonus (good), so one could, if so inclined, form the antonym based on the comparative of malus (bad), peior, leading to apeiorate. When I did the same to find an antonym for optimal (being pessimal), the result turned out to be in dictionaries. This time, no such luck. That's why I keep this as a comment, not an answer. Apeiorate is certainly not the word anyone was trying to remember.
    – oerkelens
    Oct 19, 2016 at 15:03
  • @oerkelens: It would likely be *apejorate (cf pejorative), but it's still not in any dictionary I've come across :)
    – psmears
    Aug 19, 2021 at 22:05

3 Answers 3



From WordNet (r) 3.0 (2006) [wn]:

      v 1: make worse; "This drug aggravates the pain" [syn: {worsen},
           {aggravate}, {exacerbate}, {exasperate}] [ant:
           {ameliorate}, {amend}, {better}, {improve}, {meliorate}]
      2: exasperate or irritate [syn: {exacerbate}, {exasperate},

I don't think there is an antonym that ends with an -iorate because the words ameliorate and meliorate derive from a single stem (see below). The closest etymological antonym is aggravate

ameliorate comes from French meilleur and ameliorer - the direct French antonym for this word is aggraver meaning 'to make worse'.


After I posted this, I remembered the word!


del·e·te·ri·ous adjective \ˌde-lə-ˈtir-ē-əs\
: damaging or harmful

adverse, bad, baleful, baneful, damaging, dangerous, harmful, detrimental, evil, hurtful, ill, injurious, mischievous, nocuous, noxious, pernicious, prejudicial, wicked
anodyne, benign, harmless, hurtless, innocent, innocuous, inoffensive, safe
Related Words
hostile, inimical, unfriendly; contagious, deadly, infectious, infective, pestiferous, pestilent, pestilential, poisonous, venomous; insidious, menacing, ominous, sinister, threatening; hazardous, imperiling (or imperilling), jeopardizing, parlous, perilous, risky, unsafe, unsound; nasty, noisome, unhealthful, unhealthy, unwholesome; destructive, fatal, killer, lethal, malignant, ruinous
Near Antonyms
advantageous, beneficial, useful; favorable, good, propitious; curative, healthful, healthy, helpful, palliative, remedial, salubrious, salutary, wholesome; secure, sound; benignant; noncorrosive, nondestructive, nonfatal, noninfectious, nonlethal, nonpoisonous, nonpolluting, nontoxic, nonvenomous

  • 2
    This can't be right. Ameliorate is a verb; deleterious isn't. Sep 15, 2013 at 9:45
  • 1
    They don't look exact opposite meaning either
    – Pam
    Sep 15, 2013 at 10:32
  • 1
    @BrianHooper but the OP did say in his question "sounds like detiliorate". :)
    – Mari-Lou A
    Sep 15, 2013 at 11:12