Flimsy describes something so thin, weak, or poorly made that it can't stand up to much use. A flimsy cardboard box might collapse when you try to lift it. A flimsy excuse falls apart the moment someone questions it. When something is flimsy, it lacks the strength or substance to do its job properly.

The word often suggests disappointment or frustration. Imagine building a fort from flimsy materials: the walls might wobble, the roof might sag, and the whole structure could tumble down in a light breeze. A flimsy argument in a debate crumbles under scrutiny because it's built on weak reasoning or questionable facts.

You can use flimsy for physical objects (a flimsy plastic fork that bends when you try to cut your food) or for ideas and explanations (a flimsy alibi that nobody believes). The word captures that specific feeling when something looks like it might work but proves too insubstantial when tested. Whether it's a flimsy paper airplane that won't fly straight or a flimsy promise that someone breaks right away, the word tells you something lacks the strength or quality you need to rely on it.