One of the farming types supports Partition (4)
I believe the answer is:
stud
'one of the farming' is the definition.
The definition and answer can be both acts as well as being singular nouns.
Perhaps there's a link between them I don't understand?
I don't understand the remainder of the clue.
Can you help me to learn more?
(Other definitions for stud that I've seen before include "Stallion for breeding - fastener" , "Collar fastener or horse farm" , "Male horse kept for breeding" , "virile fellow" , "Horse-breeding place" .)