prompter (Adjective) — According to schedule or without delay; on time. ex. "the train is prompt"
prompter (Adjective) — Ready and willing or quick to act. ex. "she is always prompt to help her friends"
prompter (Adjective) — Performed with little or no delay. ex. "a prompt reply"
prompter (Noun) — Someone who assists a performer by providing the next words of a forgotten speech.
prompter (Noun) — A device that displays words for people to read.