›having fallen to the bottom of the sea: They're diving for sunken treasure.Staying afloat, capsizing and sinking›at a lower level than the surrounding area: It was a luxurious bathroom, with a sunken bath.Down and downwardMoving downwardsLow, short and shallow›(of eyes or cheeks) seeming to have fallen further into the face, especially because of tiredness, illness, or old age: She looked old and thin with sunken cheeks and hollow eyes.Not fit and healthyThin or slender (of people)