Wander round surrounded by sheep (4)
I believe the answer is:
roam
'wander' is the definition.
(synonyms)
'round surrounded by sheep' is the wordplay.
'round' becomes 'o' (round can mean a round object).
'surrounded by' indicates putting letters inside.
'sheep' becomes 'ram' (male sheep).
'o' placed into 'ram' is 'ROAM'.
(Other definitions for roam that I've seen before include "Move about aimlessly" , "Walk without a specific destination" , "Wander widely" , "Ramble without purpose" , "Wander freely" .)