Conservative after beer divulges top secret (9)
I believe the answer is:
concealed
'secret' is the definition.
(similar in meaning)
'conservative after beer divulges top' is the wordplay.
'conservative' becomes 'C' (UK political abbreviation).
'after' becomes 'once' (once can mean immediately after).
'beer' becomes 'ale' (type of beer).
'top' indicates taking the first letters.
The initial letter of 'divulges' is 'd'.
'c'+'once'+'ale'+'d'='CONCEALED'
(Other definitions for concealed that I've seen before include "Not open to view" , "Hidden" , "Not accessible to view" .)