Very rapid(ly). The earliest such simile is quick as a bee, which found a place in John Heywood’s Proverbs (1546). It was followed by quick as thought, appearing in Thomas Shelton’s 1620 translation of Cervantes’s Don Quixote and in Samuel Richardson’s Clarissa (1748), among other sources. Also common in the eighteenth century was quick as lightning, with a nineteenth-century American variant, quick as greased lightning. None but the last is heard much anymore, but quick as a wink, referring to the blink of an eye and appearing in one of Thomas Haliburton’s Sam Slick stories (1843), is current, as are quick as a flash, presumably referring to lightning as well, and quick as a bunny (or rabbit), which dates from the late nineteenth century. See also like the wind; like greased lightning.