5 Pairs of Compound Words, and How They’re Compounded

By Mark Nichol

A while back, I wrote about compound words involving front and back, in and out, and up and down, and the bewildering variety of styles (open, hyphenated, and closed) for each group. Here are five more pairs of words to watch for when they’re used in compound phrases.

1. Light and Dark

To be light-headed and to be lighthearted are not strictly analogous — one is a physical sensation, and the other refers to an emotion (though it may result in a physical response) — but they are both adjectives. So, why is one (and similar compounds like light-fingered and light-footed) hyphenated and the other closed? I confess I’m in the dark. But note that compounds beginning with dark are always open (“dark days” “dark horse,” “dark matter”).

Most other noun compounds beginning with light (“light meter,” “light pen”) are open, but notice light-rail, which, like a few other compound nouns (mind-set, life-form), remain stubbornly hyphenated (though the meaning of light here differs; it’s akin to the definition in the previous paragraph). When the noun light is the last element of a compound, it’s always closed: candlelight, flashlight, searchlight.

2. Mind and Brain

I’m going to go out of my mind. Why is one simpleminded yet single-minded? Is it because one is a presumably perpetual state that a person so designated has little or no control over, while the other is a personality trait? But compounds beginning rather than ending with mind generally obey these rules: open in noun compounds (with the previously noted exception of mind-set and the obscure mind-healer, as well as the jargony mindshare) and hyphenated in adjectival compounds such as mind-bending and mind-boggling).

Brain, meanwhile, is almost always open (“brain trust,” “brain wave”); brain-dead is a rare exception.

3. Right and Wrong

Compounds employing these words for practical or moral choices are generally open (“right angle,” “wrong side”), but phrasal adjectives with prepositions (right-of-way, right-to-work) are always hyphenated.

4. Right and Left

Most compounds employing right or left as directions are open (noun phrases like “left wing,” adverbial phrases such as “right away”), but the phrasal adjectives left-handed and right-handed (also adverbs) are always hyphenated.

5. Smart and Dumb

By now, you know not to expect logic in idiomatic phrases — it’s “smart aleck” but smart-ass (or smart-mouth). Open phrasing, however, is preponderant for smart and dumb: “smart card,” “smart drug,” “dumb down,” “dumb show” (pantomime). Street-smart is hyphenated, but “street smarts” is open.

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5 Responses to “5 Pairs of Compound Words, and How They’re Compounded”

  • JK Brennan

    No wonder I’m confused. this article didn’t help much. 🙂 Seriously though, I learn by example more often than not, and if the confusion is as widespread, wwide-spread?, wide spread?, as it seems then I think I’m doomed. Haha.

  • venqax

    Very good points. I supposed we have to acknowledge the force of idiom, and just hope it doesn’t give learners the impression (as it often does) that there are no rules in English. I have always maintained that the great majority of mistakes or confusion in English comes from people not knowing the rules because they are not taught. (e.g. “the letter C can sound like a K or an S or even an SH! It’s just chaose in English! No rhyme or reason! GHOTI can spell fish! ad naus.)

    But sometimes, there really is no rule and idiom prevails. This is such a case, so far as I know. The problem is compounded by the fact that so many specialized areas– even in their publications intended for general readership– claim certain things as “terms of art”. So we get healthcare (which irks me) as one word everywhere now, or things like policymaking and even decisionmaking in govt-oriented writing in the US. When such confounding compoundings are unavoidable I always look it up, or rely on the convention I know applies at least in the area I’m dealing with. That way, even if references or examples don’t agree, I can be confident that I’m using a style acceptable SOMEWHERE at least SOME of the time.

    Just to add: I do see “brainwash/ed” as a single word, and in political writing left-wing/right-wing are often hyphenated.

  • Shelley

    Please advise if said date and time is acceptable.

  • Mark Nichol


    Dictionaries differ frequently on how compounds are styled, because usage differs, and they’re responding to usage (descriptivist), rather than dictating it (prescriptivist). And, just like researchers, lexicographers reach diverse conclusions using the same body of evidence.

    The dominant resource in publishing (in the United States, at least) is Merriam-Webster’s Collegiate Dictionary, though others are employed here and there. I recommend M-W.

  • Amanda

    I have some question about the word “simpleminded.” I checked OED and Merriam, it’s close, but when I checked Longman, it’s hyphenated. Does it mean that there is some dictionary that doesn’t align with the mainstream? Is it up to the writer to choose which one he or she to comply with? Thanks.

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