Faster is taken to mean that a lens has a larger maximum aperture, meaning more light gets in, so you can use a faster shutter speed, and hence get less motion

Faster is taken to mean that a lens has a larger maximum aperture, meaning more light gets in, so you can use a faster shutter speed, and hence get less motion blurring. Non-intuitively, because depth of field gets smaller as the aperture increases, faster lenses can also offer better separation of the subject from foreground / background features