Hyphens and the Compound Adjective

We’ve never tackled compound adjectives, here on One Step Forward, partly because it’s such a complex subject. Often you can make your sentence clearer by using an adjectival phrase or clause rather than worrying about whether to hyphenate. But today we’re going to ease your fears and explain just when to put that pesky hyphen between words in a compound adjective.

Here’s the short version: hyphenate when you place the compound adjective in the sentence before the noun.

This too-simple rule, however, does not address some specific kinds of adjectives. For instance, you would hyphenate a “one-week extension” but you would not add a hyphen to the possessive form, “one week’s extension”. And then there are compound adjectives that you write as a single word, a surefire way to confuse people.

Add to this the fact that, in a passive construction where the adjective end up as the predicate you still hyphenate. Thus you would write about a hard-core song, “This song is hard-core.” User-friendly programs are user-friendly.

Note that a compound adjective can consist of other parts of speech. You may have a noun and a participle, as with an attention-getting headline, or even a pair of nouns used to describe a third. The latter depends more on the nature of the words used than the placement. You would write about an African-American teacher but a Supreme Court decision, the space-time continuum but a real estate exam.

When the nouns refer to a well-known concept or an institution they need not be hyphenated. Thus a life insurance salesman does not require a hyphen while a roller-derby skater might. You may fill out your tax return form but only after performing a cost-benefit analysis.

“Wait!” you may cry. “Everyone knows what a cost-benefit analysis is.” But therein lies another wrinkle in the hyphenation question. Two nouns of essentially equal importance should be hyphenated when used as a compound adjective. Whether the social or the security means more, you still get a social security check if you qualify.

All of this ignores the fact that some pairs of words become a single, compound word and others do not. Skin diving stays just that when used as an adjective but skydiving is a single word. Housewarming parties get no hyphen but your house-sitter does. Adding more modifiers to a noun doesn’t change the hyphenation rules, either. The ever-popular, oft-misunderstood space-time continuum keeps all of those little dashes.

So how do you figure out whether to hyphenate commonly-used phrases? Sadly, the best answer remains the same thing your mother told you when you asked her how to spell something: look it up in the dictionary. Maybe someday I’ll be brave enough to tackle compound adverbs.