Saucy, in the main (4)
I believe the answer is:
arch
I believe this clue is a double definition.
'saucy' is the first definition.
(thesaurus)
'main' is the second definition.
(I've seen this before)
'in the' is the link.
(Other definitions for arch that I've seen before include "Way though - on foot!" , "(archaic)" , "Marble, for example" , "Mysterious - curve" , "not to go straight?" .)