New leg added to stump (7)
I believe the answer is:
nonplus
'stump' is the definition.
(thesaurus)
'new leg added' is the wordplay.
'new' becomes 'n'.
'leg' becomes 'on' (cricket term, fielding positions).
'added' becomes 'plus' (I've seen this before).
'n'+'on'+'plus'='NONPLUS'
'to' acts as a link.
(Other definitions for nonplus that I've seen before include "Perplex, confound" , "State of confusion" , "'Disconcert, puzzle (7)'" , "nothing if not negative?" , "Utterly confuse" .)