Cane perhaps drove lamb bonkers (5,4)
I believe the answer is:
modal verb
'cane' is the definition.
I know nothing about this answer so I cannot judge whether this works.
'drove lamb bonkers' is the wordplay.
'drove lamb' anagrams to 'MODAL VERB'.
Though, I am not clear how the anagram is indicated.
'perhaps' is the link.
Can you help me to learn more?
(Other definitions for modal verb that I've seen before include "Word such as can, could, may, etc" , "will possibly" .)