Definition of the word let up

The expression "let up" is a phrasal verb that originated in Middle English. It is formed by combining the particle "let" with the verb "up," which initially meant "rise" or "ascend." The verb "let" itself comes from the Old English "ltegan," meaning "release" or "allow." In the Middle English period, this word began to be used more frequently as a standalone particle, often preceding another verb to create a phrasal verb, such as "let go" or "let out." In the context of "let up," the meaning of "up" evolved from referring to movement in a vertical direction to a figurative sense of intensity or force, meaning "lessen" or "abate." So, the expression "let up" eventually came to mean "to decrease or lessen in intensity, violent force or pressure." Overall, the history of "let up" shows how language evolves over time, as new meanings arise and existing words take on new functions.