Nobleman finding love in farm building (5)
I believe the answer is:
baron
'nobleman' is the definition.
(baron is a kind of nobleman)
'love in farm building' is the wordplay.
'love' becomes 'o' (love means zero in tennis).
'in' is an insertion indicator.
'farm building' becomes 'barn' (barn is a kind of farm building).
'o' going inside 'barn' is 'BARON'.
'finding' acts as a link.
(Other definitions for baron that I've seen before include "An English lord or a magnate" , "Aristocratic title" , "Nobleman providing a portion of beef" , "Minor noble" , "Minor nobleman" .)