| let fly with let fly (with) (something) 1. to throw something or shoot something from a weapon. Police officers let fly canisters of tear gas. The guy in the leather jacket was leaping over the counter when I let fly with a soda bottle. 2. to express yourself in a way that will excite or anger others. If you disagree with the officials, it's bad form to let fly with four-letter words. When she got together with her friends, they would let fly all their innermost secrets. Etymology: based on the idea of shooting an arrow |