Illegal tackle disgusting (4)
I believe the answer is:
foul
I believe this is a double definition.
'illegal tackle' is the first definition.
'disgusting' is the second definition.
(both can mean horrible)
(Other definitions for foul that I've seen before include "See 17" , "Abhorrent" , "Illegitimate tackle" , "Disgusting" , "Violation of a sporting rule" .)