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

homeowners who are underwater on their loans

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 of underwater

• aquatic
• submarine
• submerged

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

Water cribs are the structures far out in the lake, connected by miles of underwater tunnels intended to bring clean drinking water to the city. —Rick Kogan, Chicago Tribune, 18 Feb. 2026

Several businesses along Melrose Avenue were left underwater after multiple inches of rain came rushing in. —Chelsea Hylton, CBS News, 18 Feb. 2026

Though the Pacific gets chilly, especially in winter, Point Lobos has a vibrant underwater ecosystem comprising dense kelp forests and unique fish and mammal species. —Cu Fleshman, Travel + Leisure, 17 Feb. 2026

Marquee recruits in Ohio and North Carolina all but cleared the field, New Hampshire and Illinois seem settled, and the fact Democrats are looking with greedy ambition at Alaska shows how underwater the Republican brand is with voters. —Philip Elliott, Time, 17 Feb. 2026

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