The document discusses compound adjectives, which are adjectives made up of two or more words usually separated by hyphens. It provides examples of different types of compound adjectives, including those formed with periods of time, adverbs and past/present participles, nouns and adjectives/participles, and proper nouns. The types of compound adjectives are further explained with additional examples. An activity at the end tests understanding of compound adjectives by having the reader choose the correct compound adjective to complete sentences.