underwater

adjective

un·​der·​wa·​ter ˌən-dər-ˈwȯ-tər 

-ˈwä-

1

: lying, growing, worn, performed, or operating below the surface of the water

underwater plants

2

: being below the waterline of a ship

3

a

: having, relating to, or being a mortgage loan for which more is owed than the property securing the loan is worth

b

: having, relating to, or being a stock option for which the price of the option is higher than the current market value of the stock

underwater adverb

Synonyms

• aquatic
• submarine
• submerged
• sunken

Examples of underwater in a Sentence

underwater plants don't require as much light to grow as surface plants

a vessel designed for underwater exploration

Recent Examples on the Web

This heavy iron absorbed blue light, meanwhile, the red wavelength was absorbed by the water, leaving green light to dominate the underwater view. —New Atlas, 27 Apr. 2025

The park is also home to California’s first maritime heritage underwater trail, which passes by the barges and boats that now rest below the surface of Emerald Bay. —Evie Carrick, Travel + Leisure, 27 Apr. 2025

Trump's ratings on individual issues, absent immigration, are also underwater. —Gary Langer, ABC News, 26 Apr. 2025

Sleep Under The Sea Can’t get enough of Key Largo’s beautiful underwater scenes? —Skye Sherman, Southern Living, 25 Apr. 2025

Word History

First Known Use

1627, in the meaning defined at sense 1

Rhymes for underwater

• annunciator
• imprimatur
• backwater
• bathwater
• blackwater
• breakwater
• deepwater
• edgewater
• feedwater
• floodwater
• freshwater
• granddaughter

Kids Definition

underwater

adjective

un·​der·​wa·​ter ˈən-dər-ˈwȯt-ər 

-ˈwät-

: lying, growing, worn, performed, or operating below the surface of the water

underwater plants

an underwater cave

underwater

-ˈwȯt-

-ˈwät-

adverb

Legal Definition

underwater

adjective

un·​der·​wa·​ter

1

: owing more on a mortgage loan than the property securing the loan is worth

underwater homeowners

2

: being or relating to a mortgage loan in which more is owed than the property securing the loan is worth

underwater mortgages

underwater properties