WC Fields's antepenultimate Bible (3)

I believe the answer is:

lav

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'wc fields's' is the definition.
I can't judge whether this defines the answer.

'antepenultimate bible' is the wordplay.
'antepenultimate' becomes 'l' (I can't justify this - if you can you should give a lot more credence to this answer).
'bible' becomes 'av'.
'l'+'av'='LAV'

Can you help me to learn more?

(Other definitions for lav that I've seen before include "toilet" , "Loo" , "Private place in short" .)

I've seen this clue in The Independent.

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