(as) daft as a brush

:  silly, foolish

:  mad, insane

:  frivolously merry

:  brushwood

:  scrub vegetation

:  land covered with scrub vegetation

:  a device composed of bristles typically set into a handle and used especially for sweeping, smoothing, scrubbing, or painting

:  something resembling a brush: such as

:  a bushy tail

:  to apply a brush to

:  to apply with a brush

:  to remove with passing strokes (as of a brush)

:  a brief encounter or skirmish

:  to move lightly or heedlessly