Hidden pub, 'The Queen' (5)
I believe the answer is:
inner
'hidden' is the definition.
(thesaurus)
'pub the queen' is the wordplay.
'pub' becomes 'inn' (I've seen this before).
'the queen' becomes 'er' (Elizabeth Regina).
'inn'+'er'='INNER'
(Other definitions for inner that I've seen before include "Region around bullseye" , "personal" , "Opposite of outer" , "Located or occurring closer to a centre" , "closer than magpie" .)