To appear in Russell, G. and D. Graff Fara (eds.), Routledge Companion to Philosophy of Language. Routledge.

In The Cambridge Grammar of the English Language, adjectives are characterized as expressions “that alter, clarify, or adjust the meaning contributions of nouns”, in order to allow for the expression of “finer gradations of meaning” than are possible through the use of nouns alone (Huddleston and Pullum 2002, p. 526). At a general level, adjectives gain this capability in virtue of two main characteristics, one of which is semantic and one of which is syntactic. On the semantic side, they introduce properties. On the syntactic side, they are able to function as modifiers, and so may (with some restrictions) combine recursively with nouns. The result of this combination is a new property which is typically (though not always) true of a subset of the entities that the original properties are true of, thereby providing a “finer gradation of meaning” than is possible using the noun alone. This simple picture hides many important and interesting complexities, however, which provide insights on several topics of central interest to both linguists and philosophers, including: vagueness, contextualism, relativism, compositionality, and the semantic analysis of significant phenomena such as modality. This contribution to the Routledge Companion to Philosophy of Language begins with an examination of the distributional properties of adjectives, then summarize the most prominent analyses of their meanings, and finally concludes with a look at some of the roles that adjectives have played in reasoning about the issues and phenomena mentioned above.