In English, many past and present participles of verbs can be used as adjectives. Some of these examples may show the adjective use.
Although none of the sources cited above list "young adult" as an example, each clearly expresses a preference forhyphenatingcompound modifiers.
From
Wikipedia
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Her surname is the result ofhyphenatingher maiden name and her first husband's surname.
From
Wikipedia
This example is from Wikipedia and may be reused under a CC BY-SA license.
Despite the other members of her familyhyphenatingtheir name, she insisted on not doing so.
From
Wikipedia
This example is from Wikipedia and may be reused under a CC BY-SA license.
These examples are from corpora and from sources on the web. Any opinions in the examples do not represent the opinion of the Cambridge Dictionary editors or of Cambridge University Press or its licensors.