Edge of the cheek? (3)
I believe the answer is:
lip
This clue is a double definition.
'edge' is the first definition.
(lip is a kind of edge)
'the cheek?' is the second definition.
(both can mean insolence or rudeness)
'of' is the link.
(Other definitions for lip that I've seen before include "Aural impudence" , "Edge; impudence" , "Brim" , "Top edge of a vessel" , "Oral impudence?" .)