Complete circuit is more ring-like (7)
I believe the answer is:
rounder
I believe this clue is a double definition.
'complete circuit' is the first definition.
(complete circuit of the field in the game rounders)
'more ring-like' is the second definition.
(more round or ring-shaped)
'is' acts as a link.
(Other definitions for rounder that I've seen before include "Score at baseball-type game" , "More rotund" , "complete circuit in a game" , "More spherical" , "Or under (anag.)" .)