Slightly wet in Amsterdam, perhaps (4)
I believe the answer is:
damp
'slightly wet' is the definition.
(I've seen this before)
'in amsterdam perhaps' is the wordplay.
'in' indicates a hidden word.
'DAMP' is hidden in the letters of 'amsterdam perhaps'.
(Other definitions for damp that I've seen before include "Somewhat moist" , "Rising -, TV sitcom" , "Clammy" , "Unenthusiastic" , "Slightly moist" .)