"No fly on" is a colloquial expression that is commonly used in informal speech or writing, particularly in British English. It refers to someone who is not easily fooled or deceived, a person who is astute, observant, or quick-witted. When someone is described as "no fly on," it implies that they are sharp-minded, intelligent, and capable of seeing through manipulations, tricks, or dishonesty.
The term originates from the idiom "to have flies on you," which means to be slow or lacking in intelligence. "No fly on" essentially flips this idiom, suggesting that the person being referred to does not have flies on them, implying they are bright and mentally agile.
This phrase can be used in various contexts, such as in conversations, writings, or portrayals in movies or literature. It is often used to praise someone's wit, intelligence, or ability to quickly understand a situation or see through someone's intentions. For instance, you might hear someone say, "Don't try to deceive him; he's no fly on. He will easily see through your lies."
In conclusion, "no fly on" refers to a sharp and discerning individual who is difficult to deceive. It highlights their ability to quickly understand and navigate through situations, making them astute and intelligent.
