Secret boozer with beer, half-cut (5)
I believe the answer is:
inner
'secret' is the definition.
(thesaurus)
'boozer with beer half-cut' is the wordplay.
'boozer' becomes 'inn'.
'with' means one lot of letters go next to another.
'half cut' means to take half the letters.
'beer' with half the letters taken is 'er'.
'inn'+'er'='INNER'
(Other definitions for inner that I've seen before include "(Hit on) part of target immediately next to the bullseye" , "Inside; next to the bull (archery)" , "red" , "Deep" , "Ring next to the bullseye" .)