Lipstick slip (5)
I believe the answer is:
smear
'lipstick slip' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for smear that I've seen before include "Bedaub with oily stuff - defame" , "Blur, smudge" , "Calumniate" , "Dirty mark; a libel" , "Smother" .)