What part of speech is the word extensive-use?

"Extensive-use" is not a word in the English language. It's likely a combination of two words that are meant to be used together:

* Extensive: An adjective meaning "covering or affecting a large area"

* Use: A noun meaning "the act of putting something into service"

When used together, they typically form a phrase like "extensive use," which would be a noun phrase functioning as the object of a verb or preposition.

For example:

* "The company made extensive use of its resources." (The phrase "extensive use" acts as the object of the verb "made".)

* "The report highlighted the extensive use of renewable energy sources." (The phrase "extensive use" acts as the object of the preposition "of".)