Compound modifier

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. Compound modifiers are grammatically equivalent to single-word modifiers, and can be used in combination with other modifiers. (In the preceding sentence, 'single-word' is itself a compound modifier.) 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. Compound modifiers are grammatically equivalent to single-word modifiers, and can be used in combination with other modifiers. (In the preceding sentence, 'single-word' is itself a compound modifier.) The constituents of compound modifiers need not be adjectives; combinations of nouns, determiners, and other parts of speech are also common. For example, man-eating (shark) and one-way (street). The punctuation of compound modifiers in English depends on their grammatical role. Attributive compounds—modifiers within the noun phrase—are typically hyphenated, whereas the same compounds used as predicates will typically not be (if they are temporary compounds), unless they are permanent compounds attested as dictionary headwords. 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. Note that whether a word sequence such as 'heavy + metal + detector' implies a compound adjective + noun or bare adjective + compound noun depends on the punctuation. For instance, heavy-metal detector and heavy metal detector can refer to quite different things: heavy-metal detector implies a device that detects heavy metals (wherein heavy-metal functions as a compound adjective that modifies the noun detector). By contrast, heavy metal detector, without the hyphen, refers to a metal detector that is heavy. heavy is a bare adjective that modifies the compound noun metal detector. Thus, heavy metal detector is a bare adjective + compound noun sequence. A strategy to avoid conflation of compound adjective + noun versus bare adjective + compound noun sequences is to clearly distinguish the usage of an attributive adjective and a noun adjunct. Accordingly, the phrase heavy metallic detector unequivocally employs a compound adjective to describe a weighty detector made of metal. Conventionally, and with the support of modern writing guides, compound modifiers that appear before a noun phrase must include a hyphen between each word, subject to certain exceptions. Hyphens are used in this way to prevent confusion; without their use, a reader might interpret the words separately, rather than as a phrase. Hyphens join the relevant words into a single idea, a compound adjective.