Clobber sheep behind empty garage (3-2)
I believe the answer is:
get-up
'clobber' is the definition.
(I've seen this before)
'sheep behind empty garage' is the wordplay.
'sheep' becomes 'tup' (tup is a kind of sheep).
'behind' is a charade indicator (letters next to each other).
'empty' says to hollow out the word (remove centre letters).
'garage' with its centre taken out is 'ge'.
'tup' put after 'ge' is 'GET-UP'.
(Other definitions for get-up that I've seen before include "Style of dress" , "Unusual or elaborate costume" , "Outfit" , "Jump out of bed" .)