water nymph vs water spirit

water nymph and water spirit both are nouns.

Word	Noun	Adjective	Verb	Adverb
water nymph	Yes	No	No	No
water spirit	Yes	No	No	No

As nouns, water nymph and water spirit are synonyms defined as:

Other synonyms of water nymph include water sprite.

water nymph (noun)	water spirit (noun)
(Greek mythology) any nymph of the water	a fairy that inhabits water
a fairy that inhabits water
submerged aquatic plant having narrow leaves and small flowers; of fresh or brackish water
a water lily having large leaves and showy fragrant flowers that float on the water; of temperate and tropical regions