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.

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    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
  • 1
    @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
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    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
  • 2
    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

2 Answers 2


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.


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

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