Wilt in passage (3)
I believe the answer is:
sag
'wilt' is the definition.
(thesaurus)
'in passage' is the wordplay.
'in' indicates a hidden word.
'SAG' is hidden within 'passage'.
(Other definitions for sag that I've seen before include "Spinach as used in Indian cookery" , "Lose energy" , "Slump" , "Drop" , "Sinking" .)