Lash/læʃ/ Definition 1 of 5Pro Tip 1/3Physical Force Used to describe a strong, physical action, usually in anger or frustration. The boy lashed at the tree branch with a stick. Pro Tip 2/3Sudden Movement Indicates a quick, sometimes reflexive, motion or response. The cat lashed its tail before pouncing. Pro Tip 3/3Aggressive Connotation Often associated with aggressive or violent actions, not gentle ones. In the debate, the candidate lashed into his opponent mercilessly.