Clyde's partner
I believe the answer is:
'clyde's partner' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for bonnie that I've seen before include "One of two gangsters" , "The Young Pretender" , "Leader of the 1745 Jacobite uprising" , "Clyde's partner" , "attractive to northerners" .)