Soften scowl (5)
I believe the answer is:
lower
I believe this clue is a double definition.
'soften' is the first definition.
(thesaurus)
'scowl' is the second definition.
(I've seen this in another clue)
(Other definitions for lower that I've seen before include "Farther down" , "where are trousers in relation?" , "subordinate" , "put down" , "Hereford, say" .)