In order, but no water thanks! (4)
I believe the answer is:
neat
'in order' is the definition.
(I've seen this in another clue)
'no water thanks' is the wordplay.
'no' becomes 'n' (common abbreviation y/n).
'water thanks' becomes 'eat' (I can't justify this - if you can you should believe this answer much more).
'n'+'eat'='NEAT'
'but' is the link.
Can you help me to learn more?
(Other definitions for neat that I've seen before include "Tidy - old cow!" , "cows earlier" , "Nicely proportioned" , "Well-trimmed" , "Clean and orderly" .)