5 Tips to Understand Hyphenated Words

By Mark Nichol

The complexity of rules about those little dashes that separate many words for various reasons causes so much misunderstanding that many writers just leave them out of the recipe or spill them randomly into the mixing bowl. But your compositional cuisine need not be so undisciplined. The rules may seem complicated at first, but soon you’ll be able to put hyphens in their place.

1. Adjectives

Hyphenate two adjectives united to modify a noun: “a well-trained writer.” But do so only before the noun: “a writer who is well trained.” Keep in mind, though, a convention that has arisen in which permanent open compounds, words that have been bonded together to form perpetual concepts, like “income tax” or “ice cream,” don’t take a hyphen even in phrases like “income tax records” and “ice cream cone.”

How do you know which compounds have bonded and which remain free agents? If an open compound is listed in the dictionary, it’s permanent.

2. Adverbs

But notice that these rules apply to adjectives but not to a similar-looking class of words; adverbs ending in “-ly” aren’t hyphenated to the verbs they modify: “a brightly colored shirt,” “a quickly memorized poem.” But most other adverbs are (“little-known fact,” “best-kept secret”); compounds with “least,” “less,” “most,” and “more” are exceptions.

3. Nouns

Nouns are usually compounded, too, of course (“footstep,” “mountaintop”) but some, like “life-form” and “mind-set,” resist the closure that most of their like have accepted. Compounds that can be used as verbs and nouns alike differ in that the former are often hyphenated (“I had to jump-start his car”) and the latter aren’t (“He asked me for a jump start”). Another example is “fast track”: “We fast-tracked the project,” but “It’s on the fast track.”)

4. Multiword Coumpounds

Multiword compounds like “right-of-way,” “back-to-back,” and “up-to-date” always include hyphens. Beware, though: “Head to toe,” although a common expression, does not appear in the dictionary with or without hyphens, so omit them (unless the phrase modifies a noun: “a head-to-toe inspection”). Familiar word strings that modify nouns are usually hyphenated before and after: “next-to-last person in line,” “the reply was matter-of-fact.”

5. Confusing Words

Some words in which you wouldn’t expect a hyphen to persist remain to avoid confusion with a similar word with a different meaning (“re-cover,” as opposed to “recover”; “re-creation” instead of “recreation”).

Had enough? We haven’t even covered every hyphen rule yet, but I’ll save some for later. The bottom line about this floating line, though, is: “When in doubt, look it up.”

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15 Responses to “5 Tips to Understand Hyphenated Words”

  • Nicholas Rose

    Sorry but I cannot agree on “well-trained”. Here, “well” is not an adjective. (As an adjective, applied to “writer”, it would mean that the writer is in good health!) It is an adverb and, as such, a completely separate entity. Therefore no hyphen is needed. Indeed I would consider it wrong to put a hyphen.

    A hyphen should only be used in adverb-adjective combinations where the adverb can also double as an adjective. The obvious example is “best known solution”/”best-known solution”. Here, exclusion of the hyphen makes it clear that two separate adjectives are involved, each applicable directly to the noun. The solution is the best among those that are know. Inclusion of the hyphen makes it clear that “best” is an adverb associated with “known” and not an adjective associated with “solution”, so that the meaning is clearly: the solution that is most widely known.

  • Rebecca

    Thank you for the clarification on hyphenated words. Sometimes it can be tricky as you pointed out in #5 Confusing words. I never thought to hyphenate some of those words.

  • Dayf

    How about “a two-year-old boy”? Is that correct? Can you even write “a 2-year-old boy”?

  • Ken

    Excellent post, Mark.

  • Michael

    Very useful, thanks Mark.

  • Mark Nichol


    Greater authorities than me hyphenate well as part of a phrasal adjective: The Chicago Manual of Style (15th edition), in chapter 5, item 93, coincidentally also cites well trained (and notes that the hyphen in such a construction is generally omitted when it appears after the noun), and the online version of Merriam-Webster’s Collegiate Dictionary, at http://www.m-w.com, uses the example of well-equipped. I don’t make up the rules; I just follow ’em.

  • Mark Nichol


    Yes, you can write “2-year-old-boy.” You did, and so did I. But whether you see the number spelled out or in numeral form online or in print depends on a publication’s style. Most use the word two, but a scholarly scientific text with a preponderance of references to people’s age is likely to employ figures. Bottom line: Two is much more likely than 2, and looks better, but both are correct.

    P.S.: I should say “each is correct” — generally, stick to one style or the other. And if, for a specific class of data (whether people’s ages or the number of angels that can dance on the head of a pin), you use numbers both above and below one hundred — the tipping point for spelling numbers out or using numerals, according to The Chicago Manual of Style, the bible of the book-publishing industry (and beloved of many magazine editors, too) — for consistency, use numerals for every reference to a number in that category.

  • Mike Goronsky

    A couple of typos exist above.

    4. Multiword **Coumpounds**

    What this means is that, for example, “fast acting cleanser,” especially when printed in an exuberant typeface rendered in a Day-Glo hue on a plastic bottle, is easier to read when deprived of **they** hyphen, that to insert the mark in “fast acting” to properly signal that the adjectival phrase is a single unit of meaning modifying cleanser will result in a dissonant consumer experience.

  • Mike Goronsky

    Do you agree with the hyphens in the following?

    The boy was well-behaved.
    The professor is well-known.
    He was well-respected.
    The software is up-to-date.
    The disease was non-life-threatening.


  • Mark Nichol


    Thanks for pointing out the typos.

    As for your hyphenation query, although many phrasal adjectives beginning with well are hyphenated in the dictionary, and the rule of thumb is to hyphenated the phrases so listed even when they follow a noun, The Chicago Manual of Style recommends treating well constructions the same as almost any other compound modifier, and I agree, so I would omit the hyphen in the first three sentences.

    However, I hyphenate “up-to-date” (also hyphenated in the dictionary) before and after the noun; its idiomatic pedigree is awkwardly laid bare when hyphens are omitted: “That is a fashion that is more up-to-date.” And though the prefix non is usually attached without a hyphen, one is called for when the term it is being affixed to is a compound modifier, and so the second hyphen is required, too.

    To summarize:
    The boy was well behaved.
    The professor is well known.
    He was well respected.
    The software is up-to-date.
    The disease was non-life-threatening.

  • Oliver Lawrence

    Nicholas Rose contradicts himself, I agree: “a well trained man” could mean a man who was both well (in good health) and trained, which is precisely why the hyphen is required.

    I remember reading somewhere recently that, rather than using multiple hyphens within a compound, a single dash can be used before the last of the words in the compound – where do you stand on that one?

  • Oliver Lawrence

    Examples of compound adjectives formed of two actual adjectives: a deep-red wine, a little-known man (but, as you rightly say, a wine that is deep red, a man who was little known).

  • Jason Hawthorne

    One that is puzzling me is:
    Full- and part-time jobs. Can you explain why the Full requires a hyphen and then a space?

  • Mark Nichol


    See this post about suspensive hyphenation.

  • Kathy

    Regarding well-developed, well-trained, or any other “well-” combination, if these follow a linking verb, no hyphen is used. They’re like predicate adjectives. No worry of misunderstanding, because the sentence “The man is well trained” can be reworded as “The man is trained well.” To imply that the man is healthy would need a comma (The man is well, trained). If the “well-” combinations are used as adjectives preceding their noun, then the hyphen is needed for clarity. And, yes, “up-to-date” is in the dictionary, and no entry is included without the hyphens.

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