The man wearing usual coat (5)
I believe the answer is:
sheet
'coat' is the definition.
(thesaurus)
'the man wearing usual' is the wordplay.
'the man' becomes 'he'.
'wearing' is an insertion indicator.
'usual' becomes 'set' (I am not sure about this - if you are sure you should believe this answer much more).
'he' put inside 'set' is 'SHEET'.
Can you help me to learn more?
(Other definitions for sheet that I've seen before include "Piece of paper; nautical rope" , "Piece of writing paper" , "Bedcover" , "Set of unseparated stamps" , "leaf" .)