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 are typically not (if they are temporary compounds), unless they are permanent compounds attested as dictionary headwords.