Akademik

underwater
1. adjective
a) beneath the surface of the water, or of or pertaining to the region beneath the water surface

Weve been underwater on our mortgage ever since the housing crash.

b) beneath the water line of a vessel
Syn: subaqueous, upside down
See Also: underground, underseas
2. noun
a) underlying water or body of water, for example in an aquifer or the deep ocean
b) A type of lure which lies beneath the water surface.
3. verb
to water or irrigate insufficiently
Ant: afloat

Wikipedia foundation.