Flipping hat off, notice flower (8)
I believe the answer is:
daffodil
'flower' is the definition.
(I know that daffodil is a type of flower)
'flipping hat off notice' is the wordplay.
'flipping' says the letters should be written in reverse.
'hat' becomes 'lid' (lid can informally mean a hat).
'notice' becomes 'ad' (both can mean an advertisement).
'lid'+'off'+'ad'='lidoffad'
'lidoffad' written backwards gives 'DAFFODIL'.
(Other definitions for daffodil that I've seen before include "Yellow bloom" , "Lent lily" , "Plant of the genus Narcissus" , "Yellow narcissus" , "Something yellow for spring" .)