A compound modifier (also called a compound adjective, phrasal adjective, or adjectival phrase) is a compound of two or more attributive words: that is, two or more words that collectively modify a noun.

Does an adjective modify both nouns?

If the adjective is used only for the second noun, it clearly doesn't modify the first noun. You can also use a single adjective when you're modifying a string of nouns and/or pronouns.

When there are two adjectives modify a noun?

"Cumulative adjectives" are two or more adjectives that build on one another and together modify a noun. They're consecutive. They are also called "unit modifiers." Indeed, they work together as a unit and are not independent descriptions of the noun.