Boy girl bowled over (5)
I believe the answer is:
basil
'boy' is the definition.
(I've seen this before)
'girl bowled over' is the wordplay.
'girl' becomes 'lisa' (**).
'bowled' becomes 'b' (cricket abbreviation).
'over' shows that the letters should be reversed in order.
'lisa'+'b'='lisab'
'lisab' back-to-front is 'BASIL'.
(Other definitions for basil that I've seen before include "Man" , "Aromatic leaves, used fresh or dried" , "Culinary herb" , "named Cardinal Hume" , "Boy - herb" .)