Servant traps fool in corridor (7)
I believe the answer is:
passage
'corridor' is the definition.
(I've seen this before)
'servant traps fool' is the wordplay.
'servant' becomes 'page' (page can mean a boy servant).
'traps' indicates putting letters inside.
'fool' becomes 'ass' (both can mean a stupid person).
'page' placed around 'ass' is 'PASSAGE'.
'in' is the link.
(Other definitions for passage that I've seen before include "Way through something" , "Piece of writing" , "Way through; part of text" , "Short section of text" , "Section of musical or literary work" .)