Just what are water words ?
There are two word roots that have a lot to do with water.
Hydro - from the Ancient Greek 'hydro' - water.
Aqua - from the Latin for water.
How many words beginning with hydro or hydr- can you find and what do they mean?
e.g. hydrofoil, hydroelectric, hydroplane, hydraulics..............
How many words beginning with aqua or aque- can you find and what do they mean?
e.g. aquarium, aqua vitae, aquatic, sub aqua, aqueduct..............
You will have more luck in adult dictionary I expect.
Another way to do it is to type the word root into a special
dictionary
called an
ETYMOLOGY DICTIONARY.

All this does is to tell you something of the history of the word.
Then you might have to look up the word in an
online
dictionary.

HYDROPHOBIA
Fear of water
Phobia means fear.
Hydro means water.
AQUALUNG
It's the bottle of gas that diver's wear on their backs so they can breathe under water.
Lung - breathe
Aqua - water
Water breathe or Water breath if you like.
See if you can do this for some of the words you found?