Wild flower girl seizing knight (7)
I believe the answer is:
violent
'wild' is the definition.
(I know that wild can be written as violent)
'flower girl seizing knight' is the wordplay.
'flower girl' becomes 'Violet' (violet is a feminine given name and a flower).
'seizing' means one lot of letters goes inside another (inserted letters are seized).
'knight' becomes 'n' (chess abbreviation).
'violet' going around 'n' is 'VIOLENT'.
(Other definitions for violent that I've seen before include "Furious" , "Extreme(ly aggressive)" , "not peaceful either" , "Bloodthirsty" , "Using extreme physical force" .)