Verb (used without object) : The battleship sank within two hours. His foot sank in the mud. Her head sinks into the pillows. ,The river sank two feet during the dry spell. ,The tower is slowly sinking. ,He gasped and sank to his knees. ,The field sinks toward the highway. ,the sun sinks in the west. ,Wipe the oil off before it sinks into the wood. ,to sink into slumber. ,sunk in thought. She sank into despair. ,to sink into poverty. ,The temperature sank to 30° at noon. ,Her voice sank to a whisper. ,He said it four times before the words really sank in. ,He sank down on the bench.    From Dictionary.com.