In semi-formal business writing in the United States, I often observe that writers tend to add a hyphen between a prefix and the root infinitive of verbs. In many of the cases, the resulting verb either does not appear in the dictionary at all, with or without the hyphen; or it does appear, but does not contain the hyphen.

It seems to me that the reason why we tend to insert the hyphen is because the verb, taken as a whole with its prefix, seems unnatural; so adding a hyphen is a syntactical decoration that has a similar effect to adding quotation marks around an unfamiliar word, or an invented word. The person must be thinking in their head, "Let's take this ordinary word that everyone understands, and tack on a prefix that everyone also understands... oh, wait, that sounds weird. Is that even a word? Hmm, probably not... well, I'll put a hyphen in here so that people can clearly separate the prefix from the verb and, by mentally putting the two together, understand the meaning."

Some examples:

  • "Re-opened" — All the dictionaries I could find (online, at least) give the infinitive "reopen", and some of them actually conjugate it as "reopened" in the examples.
  • "Re-tested" — I could find a few dictionaries that give the infinitive "retest", but none that specify "re-tested" as a conjugation. The only dictionary I could find with this infinitive was thefreedictionary.com; MW doesn't have it.

Another popular prefix is "un-", but that can often be substituted with an antonym; for example "undeployed" could become "removed" or "reverted deployment of...".

My questions/remarks about this tendency are as follows:

  • Obviously, if an authoritative dictionary of the English language lists the infinitive with the prefix but without a hyphen, it is an error to add a hyphen, either to the infinitive or to any conjugation. Correct?
  • If an authoritative dictionary does not list the infinitive with the desired prefix at all, and the writer wants to use the prefix with that infinitive anyway, is it more appropriate to include a hyphen or to omit it? This question is important because many business and technical scenarios require the application of unconventional prefixes to infinitives. The meaning of these words is often understood very intuitively by insular "in-groups" of readers who are colleagues and use these terms as jargon in a particular field of discourse.
  • Other than quoting the dictionary, are there any more abstract rules of the English language that I could cite to justify including (or not including) a hyphen in these cases? I am especially interested in rules that would explain, to those who think the hyphen belongs there, why it does not. If there is a general case rule that would apply to most or all cases of tacking on prefixes to existing infinitives, that would be ideal.
  • While I prefer avoiding these problems whenever possible, by using appropriate antonyms for "un-" and appropriate repetition words for "re-", sometimes it is necessary to apply a prefix and create a jargon term, or write down a jargon term that is completely entrenched in the verbal usage of a large population.
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    In my dictionary (New Oxford Dictionary for Writers and Editors) if an hyphen exist in "re-" case, it means "again": for instance, you have "sign" and "re-sign" ("sign again"), but "resign" means "voluntarily leave a job". And you have "re-serve" ("serve again") or "re-close" ("close again") and so on.
    – user19148
    Commented Oct 5, 2012 at 16:52
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    I have actually seen "resigned" used in publications to mean what you would write as "re-signed"; that is, a person was "signed" (to belong to an organization) again. Worse, it's almost an antonym of the alternative meaning of "resigned" where the 's' is pronounced like a 'z'; that's where they quit the organization! So if "re-signed" is correct, I'm very confused, given the existence of words like "retest" and "reopen" in the dictionary. Commented Oct 5, 2012 at 16:59
  • User who is supposed to possess a fuller comprehension of this question could clarify your doubts, I'm not native of English language. However the dictionary I cited reads what I reported in previsious comments. But, albeit I'm not a native, I think that the two different senses with and without the hyphen should be self-explanatory for some of these words. For another instance, think of "re-search" ("re-searched"). How can anybody confuse this word with "research" ("researched")?
    – user19148
    Commented Oct 5, 2012 at 17:07
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    Related: When is it necessary to use a hyphen in writing a compound word?
    – Kit Z. Fox
    Commented Oct 5, 2012 at 17:41
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    I'm not sure how your first question can be considered answerable. Who is to decide on which dictionaries qualify as authoritative? Dictionaries and style guides certainly do not all agree. For instance, the MACQUARIE UNIVERSITY Style guide demands re-apply and re-admission (and, one can only assume, re-admit), while Collins demands reapply and readmit. I won't check for purely dictionary differences, but am sure they exist. Commented Nov 19, 2012 at 16:33

2 Answers 2


Usually you can just slap re on the front of a word, without a hyphen, and you will be understood. There’s no need for the term to have made its way into an “authoritative” dictionary, even if there were such a thing.

There are circumstances in which the hyphen is desirable:

  • if your new word with re collides with an established “re” word which has a different sense. Two of the words Carlo_R mentions are of this sort: resign and reserve.
  • If you want to draw attention to the fact that you are using a “re” word in a different sense than that which would be expected, particularly if you are reverting to the base sense. “D.W.Griffith’s re-construction of the myth of the carpetbagger.”
  • If you want to emphasize that you are repeating or reversing an action. “Burns opened an interesting question in 1923; but it has been completely neglected and I want to re-open it now.”

I sometimes intrude a hyphen when the word to which I’m attaching re begins with a vowel, to prevent even momentary confusion; but it’s probably not necessary.

  • Fascinating insights by both of you, thanks! I'll stew on this for a day and come back and probably mark this as the answer. Commented Oct 5, 2012 at 17:31
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    The answer says everything I would have done. One might also mention recreation as needing a hyphen in some contexts.
    – Andrew Leach
    Commented Oct 5, 2012 at 17:44
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    What @Andrew said. I particularly like the way you "gloss over" OP's (imho mistaken) assumption that for any given word and context, incorporating a hyphen is either completely correct or completely wrong. There are definitely borderline cases where either choice is defensible, and two competent writers might reasonably agree to differ (and "dictionaries at dawn" would be pointless and unseemly! :) Commented Oct 5, 2012 at 20:48
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    @FumbleFingers I pick the print OED - you can do a lot of damage with that. Commented Oct 5, 2012 at 21:46
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    The use of the hyphen (rather than the formation of a closed compound) in the verb air-condition is possibly partly to ensure that the first syllable isn't assumed to be airc, but also, I'd suggest, to avoid an unsightly fusion. Sometimes, hyphenated forms are slightly easier on the eye. Commented Nov 19, 2012 at 17:29

As Stony says, usually a re doesn’t take a hyphen.

I have seen a hyphen used to distinguish homographs, such as re-creation for a new creation instead of recreation in the pastime sense.

People should remember the UK English tends to use more prefix-hyphens than US English does, but the counts of headwords beginning with “re-” plus a particular letter in the OED are as follows:

  • 200 re-e*
  • 75 re-r*
  • 43 re-a*
  • 25 re-s*
  • 22 re-c*
  • 21 re-b*
  • 13 re-f*
  • 12 re-w*
  • 11 re-p*
  • 10 re-t*
  • 8 re-l*, re-m*
  • 5 re-d*
  • 4 re-u*
  • 3 re-g*, re-i*
  • 1 re-o*, re-q*, re-v*, re-z*
  • 0 re-h*, re-j*, re-k*, re-n*, re-x*, re-y*

That includes adjectives and gerunds; if you restrict it to verbs only, the counts are:

  • 98 re-e*
  • 35 re-r*
  • 28 re-a*
  • 16 re-b*
  • 15 re-s*
  • 14 re-c*
  • 8 re-f*, re-t*
  • 7 re-m*
  • 6 re-w*
  • 5 re-l*, re-p*
  • 4 re-d*
  • 3 re-u*
  • 1 re-i*, re-o*, re-q*, re-v*, re-z*
  • 0 re-g*, re-h*, re-j*, re-k*, re-n*, re-x*, re-y*

As you see, verbs beginning with e and a often take a hyphen when prefixed with re, as it turns out do those beginning with r. I cannot explain the r’s, but with the vowels, it is to avoid creating a digraph or diphthong when they need to be in hiatus (that is, as two separate syllables). For example, some of these are ok, but some are infelicitous in the extreme:

  • re-edit, reëdit, reedit
  • re-endear, reëndear, reendear (not reindeer!)
  • re-elect, reëlect, reelect
  • re-aspire, reäspire, reaspire (not respire!)
  • re-avow, reävow, reavow
  • re-ask, reäsk, reask
  • re-up, reüp, reup
  • re-use, reüse, reuse
  • re-install, reïnstall, reinstall
  • re-ink, reïnk, reink
  • re-occur, reöccur, reoccur (but also recur)
  • re-overflow, reöverflow, reoverflow
  • re-orient, reörient, reorient

That said, the OED has both reopen and retest without a hyphen. And people seem to get by without any fanciness with coalesce and reify and such just fine, not to mention replace and restore, so perhaps they should suffer re-image spelt as reimage, too.

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    I'm sort of surprised there aren't more hyphenated forms with o. But I'm a big Tolkien fan, and my wife's a medievalist, so I probably tend more than most people to see eo as a diphthong. I betcha a lot of those re-r words are re-re, which has its own pitfalls for the reader. Commented Oct 5, 2012 at 18:01

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