This idiom means to refresh, rejuvenate, or clear one’s mind, often through physical activity, fresh air, or a change of pace. It suggests dispelling mental stagnation or lethargy, like clearing dust from a neglected space, and is used to encourage revitalization after routine or confinement.

The phrase likely emerged in 19th-century Britain, tied to the imagery of clearing cobwebs from old rooms, symbolizing renewal. An early use appears in an 1860 *All the Year Round* article by Charles Dickens: ‘A walk to blow the cobwebs away.’ It reflects Victorian ideals of fresh air and exercise as mental restoratives. By the 20th century, it was common in British and Commonwealth English, especially in contexts of outdoor activities or mental clarity.