Rigid haircut not showing a calm state of mind (6)
I believe the answer is:
frozen
'rigid' is the definition.
(thesaurus)
'haircut not showing a calm state of mind' is the wordplay.
'haircut' becomes 'afro' (I've seen this before).
'not showing' is a deletion indicator.
'calm state of mind' becomes 'zen' (calm state of mind in Buddhism).
'afro' with 'a' taken out is 'fro'.
'fro'+'zen'='FROZEN'
(Other definitions for frozen that I've seen before include "Like 7 [ICE]" , "Glacially cold" , "Film" , "Ice-cold" , "Still - very cold" .)