Read

Hyphen (-)
Hyphens are used to link words and parts of words. They are not as common today as they used to be, but there are three main cases where you should use them:
      o in compound words
      o to join prefixes to other words
      o to show word breaks
 
Hyphens in compound words
 
Hyphens are used in many compound words to show that the component words have a combined meaning (e.g. a pick-me-up, mother-in-law, good-hearted) or that there is a relationship between the words that make up the compound: for example, rock-forming minerals are minerals that form rocks. But you don’t need to use them in every type of compound word.
 
 
Compound adjectives
 
Compound adjectives are made up of a noun + an adjective, a noun + a participle, or an adjective + aparticiple. Many compound adjectives should be hyphenated. Here are some examples:
 
|noun + adjective           |noun + participle                         |adjective + participle                   |
|accident-prone             |computer-aided                           |good-looking                             |
|sugar-free                 |power-driven                             |quick-thinking                           |
|carbon-neutral             |user-generated                           |bad-tempered                             |
|sport-mad                   |custom-built                             |fair-haired                               |
|camera-ready               |muddle-headed                             |open-mouthed                             |


 
With compound adjectives formed from the adverb well and a participle (e.g. well-known), or from a phrase (e.g. up-to-date), you should use a hyphen when the compound comes before the noun:
 
well-known brands of coffee
an up-to-date account
 
but not when the compound comes after the noun:
 
His music was also well known in England.
Their figures are up to date.
 
It’s important to use hyphens in compound adjectives describing ages and lengths of...