John, whose hairstyle took any form (6)
I believe the answer is:
bunyan
'john' is the definition.
Both the definition and answer are singular nouns.
Maybe you can see an association between them that I don't see?
'hairstyle took any form' is the wordplay.
'hairstyle' becomes 'bun'.
'took' is a charade indicator (letters next to each other).
'form' is an anagram indicator (another form of the letters).
'any' anagrammed gives 'yan'.
'bun'+'yan'='BUNYAN'
'whose' is the link.
Can you help me to learn more?
(Other definitions for bunyan that I've seen before include "John . . . . . . wrote 'The Pilgrim's Progress'" , "John ... wrote 'The Pilgrim's Progres'" , "The Pilgrim's Progress author, d. 1688" , "Writer" , "Paul -, US mythic hero" .)