Cosmetic to glue on cheek (8)
I believe the answer is:
lipstick
'cosmetic' is the definition.
(lipstick is a kind of cosmetic)
'glue on cheek' is the wordplay.
'glue' becomes 'stick' (I've seen this before).
'on' is a charade indicator (letters next to each other).
'cheek' becomes 'lip' (both can mean insolence or rudeness).
'stick' put after 'lip' is 'LIPSTICK'.
'to' acts as a link.
(Other definitions for lipstick that I've seen before include "Colour applied to the mouth" , "Cosmetic used to colour around the mouth" , "Cosmetic item" , "Pick list, oddly, for the cosmetic" , "Coloured cosmetic" .)