Too old really to accept Liberal (6)

I believe the answer is:

overly

'too' is the definition.
('overly' can be a synonym of 'too')

'old really to accept liberal' is the wordplay.
'old' becomes 'o' (common abbreviation eg in OE for Old English).
'really' becomes 'very' (I've seen this before).
'to accept' is an insertion indicator.
'liberal' becomes 'l' (abbreviation).
'very' enclosing 'l' is 'verly'.
'o'+'verly'='OVERLY'

(Another definition for overly that I've seen is " Excessively".)

I've seen this clue in The Telegraph.

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