複合形容詞就是兩個以上的字用短劃符號(即連字符號) 形成的形容詞,通常置於名詞之前,用以修飾該名詞.一般而言,複合形容詞有下列數種:

1. 數字 + 名詞

不論數字詞是one或two以上,之後的名詞恆為單數.

例:

The five-year plan may take more than five years to carry out.

It's zero degrees Celsius. The zero-degree temperature is unbearable.

2. 數字詞 + 名詞 + 形容詞

數字詞之後置入連字符號再接單數名詞,置入連字符號再接形容詞

例:

John is a five years old boy.

=John is a five-year-old boy.

3.名詞 + 現在分詞

此類結構形成的複合形容詞一律由主動語態的形容詞子句化簡而成

例:

Mary is a girl who likes to break boys' hearts.

= Mary is a heart-breaking girl.

This ia an animal that eats men.

= This ia a man-eating animal.

They are people who abide by the law.

=They are law-abiding people.

4. 副詞 + 現在分詞

主動語態的形容詞子句中的動詞若為不及物動詞,且有副詞修飾時.該形容詞子句亦可化簡為複合形容詞

例:

The area which lay low was flooded.

=The low-laying area was flooded.

5.名詞 + 過去分詞

由被動的形容詞子句化簡而成

I feel sorry for the boy whose heart is broken.

=I feel sorry for the heart-broken boy.

6. 形容詞 + 名詞變成的過去分詞

此類的複合形容詞均與身體部位的器官或組織有關:

~a girl who has big eyes

= a big-eyed girl

a soldier who has only one leg

=a one-legged soldier

a snake that has two heads

=a two-headed snake

a boy who has a broken heart

= a broken-hearted boy

=a boy whose heart is broken

7.well 及 ill之後亦可加過去分詞形成複合形容詞

例:

well-behaved

well-bred

well-built

well-chosen

well-done

ill-mannered

ill-natured

ill-bred

ill-fated

The ill-fated young man committed suicide in the long run.