What is an attributive noun?
An attributive noun is used is a noun that’s placed before another noun to modify it, in the same way as an adjective. For example, in the phrase “teacher training,” the noun “teacher” is used attributively to modify another noun, “training.”
Attributive nouns are not exactly the same as adjectives. A big difference is that they can only be used in the attributive position—before the noun they modify—and not in the predicative position.
For example, you can write either “extensive training” or “training that is extensive”; but you can’t write “training that is teacher.” This is because “teacher” is just an attributive noun, not a true adjective.