It only looks like clear water (3)
I believe the answer is:
gin
This clue could be a double definition.
'it only looks' is the first definition.
The definition suggests a singular noun which matches the answer.
'clear water' is the second definition.
The definition and answer can be both man-made objects as well as being singular nouns.
Perhaps there's an association between them I don't understand?
'like' acts as a link.
Can you help me to learn more?
(Other definitions for gin that I've seen before include "Spirit; cotton machine" , "Alcohol made with juniper berries" , "Spirit, aka 'Mother's ruin'" , "Trap for catching animals" , "It often gets mixed up with this" .)