Hyphens in Prefixes
Hyphens in PrefixesA prefix is a half word (e.g., anti-, ex-, post-, pre-) placed before a word to modify its meaning. Most prefixed words can be written with or without a hyphen after the prefix.
General Guideline with PrefixesAs a general guideline, avoid the hyphen if you can, but if the unhyphenated version is a spelling mistake (let your spellchecker do its job) or looks too unwieldy for you, use a hyphen.
Here are some fixed rules:
- Always use a hyphen with "ex-" and "self-,"
- Never allow ambiguity (e.g., write "re-press the shirt" not "repress the shirt")
Read more about prefixes.
More Guidance with Hyphens in PrefixesThere is often confusion over whether a hyphen should be used with a prefix. In other words, should you write "re-consider" or "reconsider," or "anti-aircraft" or "antiaircraft"?
Unfortunately, there is no simple rule governing this, but here are some guiding principles.
Guiding Principles for Hyphens with PrefixesIf it's not a spelling mistake to avoid the hyphen and you can bear how the word looks without it, then avoid the hyphen.
Often, it's your choice whether to use a hyphen. Lots of prefixed words can be written with or without a hyphen. The underlying guideline is:
Applying the PrincipleHere are some examples to explain the guiding principle:
- antiaircraft ("Antiaircraft" is not wrong, but it looks a little unwieldy. If you feel the same way, write "anti-aircraft.")
Detailed Guidance on Hyphens with Prefix
Use a Hyphen with a Proper NounIf your prefix sits before a proper noun, use a hyphen. For example:
Do Not Allow the Same Vowel to Double UpIf the prefix ends in the same vowel that the root words starts with, separate them with a hyphen. For example:
- coowner (Your spellchecker (or dictionary) will not let you have "coowner.")
You Can Let Different Vowels Double UpWhen a prefix ends in a vowel and the root word starts with a different vowel, omit the hyphen. For example:
- semiautonomous (However, if your spellchecker doesn't like it or you cannot bear how it looks, go for a hyphen. For many, " semiautonomous" looks too unwieldy.)
Use a Hyphen with "Ex" and "Self"The prefixes "ex" and "self" are followed by a hyphen. For example:
Eliminate Ambiguity Every TimeIf the unhyphenated version could be confused with a different word, add the hyphen. (This is most common with the prefix "re." For example:
- re-cover / recover (If there were no hyphen in "re-cover," it could be confused with "recover," meaning "return to a normal state.")
- re-press / repress (If there were no hyphen in "re-press,"Could be confused with "repress," meaning "subdue with force.")
Enjoy the LeniencyMost prefixed words exist in both forms. As you might have noticed in the guidelines above, it is often down to how the writer feels about the word.
- The attack would take place at night as the anti-government troops did not possess infrared goggles. (In this example, the writer did not like the look of "antigovernment" or "infra-red," so chose the versions above. That's fine. Readability – as the writer sees it – trumps all guidelines.)
Some Common PrefixesHere are some common prefixes:
|a-, an-||without||amoral, atypical|
|com-, con-||with||companion, contact|
|en-||put into||enclose, envelop|
|ex-||out of, former||extract, ex-governor|
|extra-||beyond, more than||extracurricular|
|il-, im-, in-, ir-||not, without||illegal, impractical, inconsiderate, irresponsible|
|non-||not, without||nonentity, nonstarter,|
|omni-||all, every||omnipresent, omniscient|
|pre-, pro-||before, forward||precede, project|