Group of actors back for a month (4)
I believe the answer is:
adar
'month' is the definition.
(I know that Adar is a month)
'group of actors back for a' is the wordplay.
'group of actors back' becomes 'dar' (I can't justify this - if you can you should give a lot more credence to this answer).
'for' means one lot of letters go next to another (I've seen this in other clues).
'dar' put after 'a' is 'ADAR'.
Can you help me to learn more?
(Other definitions for adar that I've seen before include "period for Jewish people" , "Jewish month" , "month in Israel?" .)