Clobber two animals going west (6)
I believe the answer is:
tackle
'clobber' is the definition.
(I've seen this before)
'two animals going west' is the wordplay.
'two animals' can mean two substitutions for 'animal'.
'animal' becomes 'elk' (I have seen 'American animal ' mean 'elk' so perhaps 'animal' could also mean 'elk').
'animal' becomes 'cat' (cats are animals).
'going west' shows that the letters should be reversed in order (letters heading to the west or left).
'elk'+'cat'='elkcat'
'elkcat' back-to-front is 'TACKLE'.
(Other definitions for tackle that I've seen before include "Compete for ball" , "In rugby, intercept opponent running with ball" , "Robust feature of football" , "Take on; rigging" , "things" .)