Mew up (also spelled mew-up) is a phrasal verb that means to confine or shut up in a small or restricted space, or to close or seal off an area. Synonyms for this term include imprison, detain, enclose, confine, isolate, seal, and fence in. Other similar expressions include hem in, cordon off, barricade, box in, wall off, and lock up. The word mew comes from the Middle English term mewe, meaning a cage or coop for hawks. Today, the term mew up is most commonly used in reference to animals, particularly cats, which are often kept indoors or confined to small spaces.