Cat in large wood (4)
I believe the answer is:
lash
'cat' is the definition.
(I've seen this in another clue)
'large wood' is the wordplay.
'large' becomes 'L' (eg in clothes sizes).
'wood' becomes 'ash' (wood from an ash tree).
'l'+'ash'='LASH'
'in' acts as a link.
(Other definitions for lash that I've seen before include "Whip; securely fasten" , "Strike with a whip" , "Flog" , "over the eye" , "Stroke of the whip" .)