With water drained away notice spirit (5)
I believe the answer is:
dryad
'spirit' is the definition.
(type of spirit in Greek myth)
I cannot understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for dryad that I've seen before include "minor divinity" , "Nymph of the woods" , "Tree nymph" , "Beautiful young woman" , "Mythological wood nymph" .)