I was confused by the roles of nouns in English. It seems that nouns can modify verbs as stated in this qeustion and adjectives in these examples:

Do You Know How to Be Street Smart?
... the prior predictive kernel distributions are not orders of magnitude different from the observed data.


  1. https://kidshealth.org/en/kids/street-smart.html
  2. https://www.nature.com/articles/s43586-020-00001-2

I wonder if the two types of nouns act the same role? In the above sentence is street acting as an adverb? Or something else? When can we modify adjectives with nouns?

  • 2
    I think these are compounds, like the noun-verb compounds referred to in your other question. Street smart = knowing how to look after yourself in public places. Other examples that occur to me are book learned = having acquired one's knowledge from books, and trigger happy = prone to firing guns irresponsibly. Mar 28, 2021 at 16:41
  • 2
    "Street-smart" is a compound adjective, where the first base is a noun and the second an adjective. Note the hyphen.
    – BillJ
    Mar 28, 2021 at 17:29
  • 4
    You are making a common ELL mistake - thinking than an idiom reveals some hidden rule of grammar. It doesn’t. This is an idiom. Mar 28, 2021 at 22:36
  • Well, I dunno, it may not be official but in many cases, like this one, it has a predictable "rule" of its own and will sound even more awkward to native speakers if it's done other than according to that rule. But it's true that it's not a sign that the official rules of grammar allow for this, it's just defying them.
    – A. B.
    May 18, 2021 at 7:41

1 Answer 1


Do You Know How to Be Street Smart?

Q. In the above sentence is street acting as an adverb? Or something else? When can we modify adjectives with nouns?

A.1 Street-Smart is an adjective and is the American translation of The UK's "streetwise" Ref C.E.D.


Attributive Nouns - A noun can also be used like an adjective to modify another noun. Ref Grammar Monster

For example: diamond ring; car door

In these examples, the examples "diamond," and "car" are functioning like adjectives. When nouns are used like this, they're called "attributive nouns."

Compound Adjective - A compound adjective is a single adjective made up of more than one word. The words in a compound adjective are usually grouped together using hyphens to show it is a single adjective. Ref Grammar Monster

Here are some example of compound adjectives:

four-foot table, 12-page magazine, free-range eggs, never-to-be-forgotten experience, well-deserved award

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