What a bull might do to you is arguable (4)
I believe the answer is:
toss
'what a bull might do' is the definition.
The definition suggests a singular noun which matches the answer.
'to you is arguable' is the wordplay.
I cannot quite understand how this works, but
'to' is found in the answer.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for toss that I've seen before include "Chuck" , "Ditch" , "Do it with caber in Scotland" , "'Flip, a coin or pancake say (4)'" , "Throw into the air" .)