Silly, foolish (4)
I believe the answer is:
daft
I believe this is a double definition.
'silly' is the first definition.
(I've seen this in other clues)
'foolish' is the second definition.
(I've seen this before)
(Other definitions for daft that I've seen before include "'---- as a brush': dotty" , "Scatty" , "Idiotic" , "Potty" , "Informally crazy as a brush" .)