Guts pub on peninsula (7)
I believe the answer is:
innards
'guts' is the definition.
(I've seen this before)
'pub on peninsula' is the wordplay.
'pub' becomes 'inn' (an inn is a type of pub).
'on peninsula' becomes 'ards' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'inn'+'ards'='INNARDS'
Can you help me to learn more?
(Other definitions for innards that I've seen before include "Internal organs" , "Guts of mechanism" , "Informal intestines and organs" , "Informally, stomach and bowels" , "Most of haggis" .)