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

With the hair setting a high standard, artist Krystal Dawn ensured the makeup didn’t miss a beat, painting an underwater portrait in shimmery white, baby blue and royal blue hues over Madix’s eyes. — Kaleigh Werner, Footwear News, 13 July 2026

From an underwater viewing area, Chinita Head, 52, stared past the glass alongside her 6-year-old nephew, Christian Walker. — Finnegan Belleau, Chicago Tribune, 13 July 2026

Macron, the longest serving of the bunch at nearly a decade, has been underwater in approval since mid 2017. — Brady Knox, The Washington Examiner, 11 July 2026

George Tzikas, a Sacramento County Regional Parks ranger, explained that the river’s currents can change, and that its underwater topography is often a contributing factor in many rescues. — Reeti Malhotra july 10, Sacbee.com, 10 July 2026

Word History

First Known Use

1627, in the meaning defined at sense 1

Rhymes for underwater

• imprimatur
• auteur
• blotter
• cotter
• daughter
• hotter
• mater
• otter
• plotter
• rotter
• slaughter
• spotter

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