[adjective], [adverb] [not gradable] - under the surface of the water, esp. under the surface of the seaan underwater camera (= a camera that you can use under water)underwater currentsunderwater photographySome species of turtle can remain underwater for 24 hours.She pushed his head underwater.
UNDERWATER
Meaning of UNDERWATER in English
Cambridge English vocab. Кембриджский английский словарь. 2012