Words that function as compound adjectives may modify a noun or a noun phrase. Take the English examples "heavy metal detector" and "heavy-metal detector". The former example contains only the bare adjective "heavy" to describe a device that is properly written as metal detector; the latter example contains the phrase "heavy-metal", which is a compound noun that is ordinarily rendered as heavy metal absent an accompanying adjective. In the latter example, however, "heavy-metal" functions as a compound adjective that modifies the noun "detector".