Given a word, say deregulate, is there a prefix to denote the opposite, rather than simply saying regulate? It seems fairly illogical to have one but I was wondering if something existed.

  • 6
    Erm... in general, the opposite of a word prefixed by de- is simply the word - without the prefix. There is nothing illogical about the fact that English doesn't have a specific prefix to mean "not negated". If we had such a prefix, we'd presumably need to put it in front of practically every word we ever used! Oct 24, 2011 at 13:11
  • 2
    @FumbleFingers If you re-read my question (pun intended) I'm saying that it IS illogical to have one, however "I was wondering if something existed."
    – jakerinker
    Oct 26, 2011 at 5:26
  • 3
    Well, the need for any such "double negation" would be rare indeed, but maybe un- fits the bill. My dictionary lists, for example, undefaced. Oct 26, 2011 at 13:35
  • 3
    Another de also fits the bil: de-deregulate. :)
    – Kaz
    Feb 13, 2013 at 1:19
  • These word game questions don't work for me. There is no "opposite" of de. De means to remove from or take out of or to deduct from. How can that have an "opposite"??
    – Lambie
    Mar 22, 2021 at 14:53

4 Answers 4


Merriam-Webster's Eleventh Collegiate Dictionary (2003) lists several words in which the prefix un- negates a word that de- has previously negated:

  • undeciphered
  • undecomposed
  • undefoliated
  • undeformed

Such instances are quite rare, however, in comparison to the number of words that use re- to override a de- negation. Thus, for example, if a doctor decontaminates a wound with antiseptic, but bacteria later reappear, we say that the new germs "recontaminate" the wound, not that they "undecontaminate" it. Among the word pairs that follow this model are:

  • decertify/recertify
  • declassify/reclassify
  • decolonize/recolonize
  • decommission/recommission
  • deconsecrate/reconsecrate
  • deconstruct/reconstruct
  • deemphasize/reemphasize
  • deenergize/reenergize
  • deescalate/reescalate
  • dehydrate/rehydrate
  • deinstitutionalize/reinstitutionalize
  • delegitimize/relegitimize
  • delist/relist
  • demilitarize/remilitarize
  • denationalize/renationalize
  • depolarize/repolarize
  • depopulate/repopulate
  • deregulate/reregulate
  • desegregate/resegregate
  • deselect/reselect
  • desensitize/resensitize
  • destabilize/restabilize
  • detach/reattach

Not all of these pairs are exact opposites (and certainly not in all senses of each term), but a number of them are very nearly so.

Still, noting the existence of this group of paired opposites is very far from saying that replacing a de- prefix with a re- prefix negates the word that de- was attached to. I suspect that Teresa, who contributed an earlier answer nominating en- as a possible negating prefix for words containing the de- prefix, had a similar (albeit smaller) set of opposed word pairs in mind:

  • decamp/encamp
  • decipher/encipher
  • decode/encode
  • decrypt/encrypt
  • dethrone/enthrone

Unfortunately, the two instances that Teresa put forward to show en- in direct opposition to de- weren't good examples; but her argument about en- does have some validity, as the five word pairs above demonstrate.

Ultimately, the simple answer to the general question raised in the original post is that no prefix consistently and reliably undoes the negation that de- (or un- or dis-, for that matter) introduces.

  • Indeed. And as a general principle, derivational morphology like this is irregular at best and almost totally unpredictable in general. So nobody should expect any more regularity than what's shown here. In fact, this is much more regular than usual, possibly due to the fact the de- and re- are scraps from Latin with some meat left on them. Aug 4, 2023 at 14:56
  • As most of Mr. Yargs' answers, this one provides a very detailed discussion of the general matters that are in the background of the OP's concerns. It, however, does not very explicitly address the specific problem of ?-regulate. So far as I understand, it may be taken to imply that reregulate is the best option, and that the only reason for somebody's hesitating to use it is that it involves two re syllables next to each other. Is that the answer, then? (Incidentally, unde- to my ear usually suggest that the de- action has not yet taken place, rather than that it has been undone.)
    – jsw29
    Oct 12, 2023 at 15:28

Regulate means to control or direct according to rule, principle, or law.

Deregulate means to remove regulations.

Re-regulate could mean to add regulations again, possibly after they've had been removed.

If you're doing something for the first time, simply using the root word is sufficient. If you're doing something a second time, you could use a re- prefix, but check for each word.

  • Dere-regulate could mean to remove the re-regulations again, when does it just go back to regulate? Warren G might know?
    – Fuzzybear
    Jul 10, 2020 at 10:16

Simply removing the 'de' would work, or using PRO-? deregulate -> regulate -> proregulate; degenerative -> generative -progenerative; On the other hand, since those de-words were not all created strictly logically it seems impossible to come up with a perfect solution to satisfy the original goal here.


I'd like to propose that ‘Do’ would be the correct prefix in my opinion.

If you look at the word devour, the definition is to eat up, or oddly enough, to DE-stroy. Or even DE-finition.. makes me want to research those words more as well. Especially DE-finition or I could write it like deafenision or the loss of one’s ability to perceive correctly. That’s a whole essay for later though lol. Back to the point of the topic, based on the other researchers responses there appears to be no official antonym to the Latin prefix dé, however, after reading the definition of dé I googled the Latin prefix that would mean to add something and the word ‘do’ came up.

Nothing much in English that I’ve found yet uses ‘do’as a prefix. In my opinion that seems intentional. Nonetheless, the opposite of taking away is obviously to give or add to. Which when you look up the definition for the word ‘do’ you will see it clearly includes that.

If you look at the word devour with me, the Latin version was spelled, devorer, de+vorer. Then look at the definition for the Latin word vorer. It means: to eat. Especially the Greek version. So I’d like to publicly propose a new word to the English language for the people. Dovour. Take it or leave it.

  • "Nothing much in English that I’ve found yet uses ‘do’as a prefix. In my opinion that seems intentional." Intentional...how? I do hope you take a moment to tour the site and see the EL&U help center, and welcome.
    – livresque
    Aug 4, 2023 at 14:07
  • I'm afraid that this is not the site on which to propose neologisms, at least without a very good case being made.
    – Andrew Leach
    Aug 5, 2023 at 11:59

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.