De-wrinkle (4)
I believe the answer is:
iron
'de-wrinkle' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for iron that I've seen before include "Former dividing line across Europe" , "resolve" , "A magnet attracts it" , "The one who was 'not for turning'" , "Remove creases from" .)