MUCH definition: great in quantity, measure, or degree. See examples of much used in a sentence. Synonyms for MUCH: significant, important, major, big, historic, substantial, meaningful, eventful; Antonyms of MUCH: little, small, slight, trivial, minor, insignificant, unimportant, negligible Much is an adjective that refers to a large quantity, amount, or degree of something. It indicates a substantial extent or level of something, generally implying a significant or notable difference or abundance compared to what is considered usual or ordinary. (in combinations such as ' as much ', ' this much ') Used to indicate, demonstrate or compare the quantity of something. MUCH meaning: 1. a large amount or to a large degree: 2. a far larger amount of something than you want or need…. Learn more. MUCH definition: 1. a large amount or to a large degree: 2. a far larger amount of something than you want or need…. Learn more. 1. A large quantity or amount: Much has been written. 2. Something great or remarkable: The campus wasn't much to look at. The meaning of MUCH is great in quantity, amount, extent, or degree. How to use much in a sentence. Much is used as an adjective or adverb, but it always means a large quantity, extent, or degree. When something hurts very much, it's very painful, and when your friend says your gift is very much appreciated, she's emphasizing how happy it made her. Much definition: Great in quantity, degree, or extent.