More confident as litigant, suppressing resistance (5)
I believe the answer is:
surer
'more confident' is the definition.
('sure' can be similar in meaning to 'confident')
'litigant suppressing resistance' is the wordplay.
'litigant' becomes 'suer'.
'suppressing' is an insertion indicator.
'resistance' becomes 'r' (abbreviation).
'suer' placed around 'r' is 'SURER'.
'as' is the link.
(Other definitions for surer that I've seen before include "More certain and positive" , "more right?" , "faster" .)