Form of play-acting by The Mod movement (6)
I believe the answer is:
method
'form' is the definition.
(thesaurus)
'by the mod movement' is the wordplay.
'by' says to put letters next to each other.
'movement' indicates anagramming the letters.
'the' after 'mod' is 'modthe'.
'modthe' is an anagram of 'METHOD'.
'of play-acting' is the link.
I am not very happy about this link. Some or all of it may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for method that I've seen before include "'Means, way of achieving (6)'" , "System, perhaps even in madness" , "Type of acting" , "System (of acting?)" , "Mode, procedure" .)