Descended gradually

• Dropped to the bottom of the lake
• Defeated, in Battleships
• Went down like a rock
• Dropped, as spirits
• Dropped to the bottom of a lake, say
• Dipped
• Foundered
• Dropped, maybe
• Visited Davy Jones' locker, in a way

The Collaborative International Dictionary Word definitions in The Collaborative International Dictionary
Sank \Sank\ (s[a^ ng]k), imp. of Sink .