Gay Lib - the nonconformist assembly (6)

I believe the answer is:

blithe

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'gay' is the definition.
(I've seen this before)

'lib the nonconformist assembly' is the wordplay.
'lib the' can be anagrammed to 'BLITHE'.
However, I'm not clear how the anagram is indicated.

Can you help me to learn more?

(Other definitions for blithe that I've seen before include "Merry" , "Joyful and unconcerned" , "'Hail to thee, ,,,,,, spirit'- Shelley (6)" , "Gay" , "Innocently happy" .)

I've seen this clue in The Globe and Mail.

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