Outside entrance to Oratory, interrogate a primate (7)
I believe the answer is:
gorilla
'primate' is the definition.
(gorilla is a kind of primate)
'outside entrance to oratory interrogate a' is the wordplay.
'outside' means one lot of letters goes inside another.
'entrance to' says to take the initial letters.
'interrogate' becomes 'grill' (I've seen this before).
The first letter of 'oratory' is 'o'.
'o' placed into 'grill' is 'gorill'.
'gorill'+'a'='GORILLA'
(Other definitions for gorilla that I've seen before include "Largest anthropoid ape" , "Primate - sturdily-built aggressive man" , "brutal man" , "big mammal" , "The biggest ape" .)