grinning like a cheshire cat

The phrase "grinning like a Cheshire cat" refers to a wide, mischievous, and somewhat eerie smile that someone might wear on their face. The expression is derived from Lewis Carroll's famous novel "Alice's Adventures in Wonderland," where the Cheshire Cat is depicted as a mysterious character known for its broad smile that often lingers even after its body disappears. Thus, when someone is described as grinning like a Cheshire cat, it implies that their smile is particularly noticeable, conspicuous, or perhaps sly.