The crossword solution for the term 'Letting Fly' is 'Loosing'. Loosing is an action that involves releasing something, usually with force. It can be used to describe the act of releasing a grip on something, or the act of releasing an object from one's hand. It can also be used to describe the act of releasing an emotion, such as anger or frustration. In this context, 'Letting Fly' could refer to the act of releasing something with force, such as throwing a ball or releasing a bow and arrow.