Definition of let on

The phrase "let on" is an English idiom that means "to reveal a secret" or "to inform quietly." Its origins can be traced back to the 16th century when it was first recorded in the English language. In Old English, the word "on" was used as a preposition meaning "on," "in," or "up." Over time, it evolved into a grammatical particle used to indicate the past participle in verbs, such as "let on" in phrases like "let on doing" or "let on seeing." The verb "let" originated from the Old English "letan," meaning "to allow" or "to permit." It was also used as a euphemism for "tell" or "reveal," perhaps due to its association with allowing information to become known. The origin of "let on" as a specific idiom is likely related to letting out a secret through subtle cues or hints, as opposed to openly revealing it. Its use as a quieter alternative to "tell" or "reveal" still persists in contemporary English, making it a common idiom in everyday conversation. Overall, the exact origins of "let on" are not entirely clear, but it is a fascinating example of the way that language evolves and reminds us of the rich history of English as a vigorous and dynamic linguistic medium.