French for 'water' (3)
I believe the answer is:
eau
'french for water' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for eau that I've seen before include "Perrier water" , "Water in France" , "French water from chateaux" , "Quick to notice things" , "Popular toilet water - . . . de Cologne" .)