Tidy up - start in the passage (7)
I believe the answer is:
transit
'the passage' is the definition.
('transit' can be a synonym of 'passage')
'tidy up start in' is the wordplay.
'tidy up' indicates an anagram (I've seen this in other clues).
'start'+'in'='startin'
'startin' with letters rearranged gives 'TRANSIT'.
(Other definitions for transit that I've seen before include "In - - (en route)" , "Pass across/through" , "Moving" , "Haulage" , "carriage" .)