Rules for using hyphens are complicated, and anybody who has to do a lot of writing should have a good reference manual handy. Here are some useful guidelines:
- Compound adjectives are generally hyphenated when they come before a noun: a gas-guzzler car, a four-story building, a five-year-old child.
- Compound adjectives are generally not hyphenated when they follow a noun: the car is a gas guzzler, the building is four stories, the child is five years old.
- Some compound adjectives are always hyphenated whether they come before or after a noun. Such permanently hyphenated compound adjectives will appear as hyphenated in an up-to-date dictionary (or in a dictionary that is up to date): short-term, part-time.
- Combinations of adverbs that end in –ly and adjectives are never hyphenated: purely selfish motives, completely absurd ideas.
- Combinations of adverbs that don’t end –ly and adjectives are hyphenated when they come before a noun: her long-awaited arrival (but Her arrival was long awaited.) Comparatives and superlatives—more, most, better, best, less least—are not hyphenated: the best laid plans, the most egregious errors. Compound adjectives in which the second element is a number are not hyphenated: a grade 3 student.
- The current trend is not to hyphenate words prefixed by non, un, in, dis, co, anti, hyper, pre, re, post, out, bi, counter, de, semi, mis, mega, micro, multi, inter, over, under: unaffiliated, nonemergency, uninfected, inpatient, disorder, disbar, coworker. But there are many exceptions. If the prefixed word begins with the same letter that the prefix ends in or is capitalized, it is hyphenated: anti-intellectual, un-American. Double e’s and double o’s are usually made into one word: reenter, coordinate. The prefixes self-, all-, and ex- almost always require a hyphen: ex-wife, self-confident, all-knowing Hyphens are also used with prefixes to avoid confusion: for example, re-count meaning “to count again” is hyphenated to distinguish it from recount meaning “to tell.” A hyphen is used to avoid the occurrence of three letters together: bell-like.
- Recent two-word technological terms have tended to evolve into single words (closed compounds.) For example, email, online, and database are replacing earlier two-word or hyphenated forms.
- Frequently used compound nouns such as data processing, home office, car insurance are not hyphenated when they are used as adjectives: a car insurance policy, the data processing department.
When in doubt always check a current dictionary or reference manual.
Choose the correct form:
- The play was a (low-budget/low budget) production.
- The Prime Minister is (well-known/well known) for his fashion sense.
- Unfortunately, the repair was (out-of-warranty/out of warranty) by the time it was done.
- The plan for Iraq has to be (fine-tuned/fine tuned) fairly soon.
- Even a (carefully-planned/carefully planned war) can go awry
- The gangster was a (friendly-looking/friendly looking) fellow.
- Conrad owns a (filthy-magazine /filthy magazine) store in Moose Jaw.
- Please (re-submit/resubmit) your application with details of the “extensive” experience you’ve had.
- You’ll have to (re-sort/resort) these cards.
- We bought a (better-built/better built) mousetrap.
- Amanda was diagnosed with (Type-2/Type 2) diabetes.
- Why is the (checkout/check-out) line always flanked by magazines featuring diet plans on one side and candy bars on the other?
- It takes a lot of work to become a (first-class/first class) chess player.
- I found an interesting (web-site/website) devoted to debunking astrology.
- After completing a PhD in philosophy, she became a (real-estate/real estate) agent.
Answers: 1. low-budget 2. well-known 3. out of warranty (Before the noun, it would be hyphenated: an out-of-warranty repair.) 4. fine-tuned (Although one encounters fine tuned, dictionaries give fine-tuned.) 5. carefully planned 6. Friendly-looking (Here friendly is an adjective.) 7. Either is correct, depending on the meaning (If Conrad owns a store that sells filthy magazines, the hyphen serves to distinguish it from a magazine store that happens to be filthy.) 8. resubmit 9. re-sort (Resort has another meaning.) 10. better built. 11. Type 2 12. checkout 13. first-class (As an adjective first-class is always hyphenated. As a noun, it isn’t hyphenated: He was of the first class.) 14. website (Originally, Web site was more common.) 15. real estate