Sheepish round wine supplier (5)
I believe the answer is:
ovine
'sheepish' is the definition.
(I've seen this in another clue)
'round wine supplier' is the wordplay.
'round' becomes 'o' (o is a circular letter).
'wine supplier' becomes 'vine' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'o'+'vine'='OVINE'
Can you help me to learn more?
(Other definitions for ovine that I've seen before include "Like the Cheviots" , "1/6 = 2/3 of 28 [SHEEPISH" , "Sheep-like" , "Relating to sheep" , "like a mug" .)