scooter vs water scooter

scooter and water scooter both are nouns.

Word	Noun	Adjective	Verb	Adverb
scooter	Yes	No	No	No
water scooter	Yes	No	No	No

As nouns, scooter and water scooter are synonyms defined as:

Other synonyms of scooter include sea scooter.

scooter (noun)	water scooter (noun)
large black diving duck of northern parts of the Northern Hemisphere	a motorboat resembling a motor scooter
child's two-wheeled vehicle operated by foot
a wheeled vehicle with small wheels and a low-powered gasoline engine geared to the rear wheel
a sailing vessel with runners and a cross-shaped frame; suitable for traveling over ice
a motorboat resembling a motor scooter