underwater

adjective

un·​der·​wa·​ter ˌən-dər-ˈwȯ-tər How to pronounce underwater (audio)
-ˈwä-
Synonyms of underwaternext
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

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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
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
By adding a company with a long record in underwater robotics, Elbit gains access to specialist expertise that complements its existing surface, sensor, communications and command-and-control capabilities. — Prabhat Ranjan Mishra, Interesting Engineering, 23 Oct. 2026 The increase comes amid continuing worries about golden mussels, an invasive bivalve from China that reproduce rapidly and attach to boats, trailers, pipes, pumps and other underwater surfaces. — Daniel Hunt, Sacbee.com, 23 Oct. 2026 The county maintains the underwater land that would house the marina piers is part of the same piece of real estate as the upland Seaquarium property. — Douglas Hanks, Miami Herald, 21 Oct. 2026 The team collected samples and filmed the plume with an underwater drone to make a three-dimensional map. — Alec Luhn, Scientific American, 20 Oct. 2026 See All Example Sentences for underwater

Word History

First Known Use

1627, in the meaning defined at sense 1

Time Traveler
The first known use of underwater was in 1627

Rhymes for underwater

See All Rhymes for underwater

Browse Nearby Words

underwaist
underwater
underway
See all Nearby Words

Cite this Entry

“Underwater.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/underwater. Accessed 27 Oct. 2026.

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Kids Definition

underwater

adjective
un·​der·​wa·​ter ˈən-dər-ˈwȯt-ər How to pronounce underwater (audio)
-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
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