Some adjectives are formed by joining two or more words with a hyphen between them to show that it is one adjective. They are called compound adjectives.
Compound adjectives are formed in many ways:
|adjective + noun + ed||long-haired, green-eyed|
|adjective + verb + ing||good-looking, fast-talking|
|adjective + noun||high-quality, low-fat|
|noun + adjective|
world-famous, sugar-free, ice-cold
|noun + noun||part-time|
|noun + present participle||mouth-washing, English-speaking|
|noun + past participle||sun-dried, hand-made|
|adverb + past participle||well-known, densely-populated|
|adverb + verb + ing||rapidly-growing, hard-working|
|number + noun||ten-dollar, one-way|
If and is possible to use between the two words, then a hyphen isn't necessary.
She has a big blue book. (She has a big and blue book.)
Use a hyphen when the compound adjective comes before the noun it modifies, but not when it comes after the noun.
It was quite a thought-provoking book.