Eyeliner problem (5)
I believe the answer is:
smear
'eyeliner problem' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for smear that I've seen before include "Discredit" , "Spread a greasy or sticky substance over something" , "Unwarranted accusation" , "allegation" , "Smother" .)