1) Concave 2) Deep set 3) Drowned 4) Flooded 5) Hollow 6) Recessed 7) Submerged 8) Swamped 9) Thin 1) Deep-set 2) Having a sunken area 3) Hollow 4) Hollow; recessed 5) Like some living rooms 6) Like some treasure 7) Like some treasures 8) Like the titanic 9) Recessed 10) Submerged 11) Under water 
• of Sink • (a.) Lying on the bottom of a river or other water; sunk.
Sunk'en adjective Lying on the bottom of a river or other water; sunk. 
[adj] - under water
adjective under water; e.g. at the bottom of a body of water; `sunken treasure`; `a sunken ship`
having sunk or been sunk beneath the surface; submerged. · having settled to a lower level, as walls. · situated or lying on a lower level: a sunken living room. · hollow; depressed: sunken cheeks.