Inclined to have a fast round (5)
I believe the answer is:
leant
'inclined' is the definition.
(I've seen this before)
'a fast round' is the wordplay.
'fast' becomes 'lent' (I've seen this before).
'round' is an insertion indicator.
'a' inserted inside 'lent' is 'LEANT'.
'to have' acts as a link.
(Other definitions for leant that I've seen before include "Slanted" , "Tipped" , "Inclined (towards)" , "bent over" , "Had tendency" .)