Intermediate 📐 Grammar · #129 of 305

Compound Adjectives

Join words with hyphens.

Examples

  • a well-known actor
  • a five-year plan

Key rules

  • Form: noun/adjective/number + participle or noun
  • Number compounds are singular: a ten-year-old boy
  • Use hyphens before a noun
  • Common: well-known, part-time, old-fashioned

Common mistakes

  • A five-years-old child → A five-year-old child
  • She is a well known singer → She is a well-known singer
💡 Tip: No plural s inside a compound adjective.
Practise this topic in the appPractise Intermediate quiz
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Related Intermediate topics

See all Intermediate grammar lessons →

Present Perfect Continuous

have been + -ing stresses duration up to now.

Past Perfect

had + past participle for an earlier past action.

Past Perfect Continuous

had been + -ing for duration before a past moment.

Future Continuous

will be + -ing for actions in progress at a future time.

Future Perfect

will have + past participle for completion before a future time.

Future Perfect Continuous

will have been + -ing for duration up to a future point.