Calm man's after some smut (6)
I believe the answer is:
soothe
'calm' is the definition.
(thesaurus)
'man's after some smut' is the wordplay.
'man' becomes 'he' (**).
'after' says to put letters next to each other.
'some smut' becomes 'soot' (I've seen this before).
'he' after 'soot' is 'SOOTHE'.
(Other definitions for soothe that I've seen before include "Appease" , "Assuage, calm" , "Cause to feel better" , "Gently calm" , "Calm; relieve pain" .)