Obtain a sheep that came back (3)
I believe the answer is:
get
'obtain' is the definition.
(I know that obtain can be written as get)
'a sheep that came back' is the wordplay.
'a sheep' becomes 'teg' (I've seen this before).
'that came back' shows that the letters should be reversed in order.
'teg' in reverse letter order is 'GET'.
(Other definitions for get that I've seen before include "Procure or secure" , "Understand" , "Procure from vegetables" , "Escape" , "Receive; obtain" .)