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to sink (e.g. a ship); to submerge
to lower (e.g. one's body into a chair)
to floor (an opponent)
激しい海戦の末、敵艦隊の主力船を海底に沈めた。
We sank the enemy ship in battle.
泥のついた野菜をバケツの水に沈めてよく洗った。
I submerged the vegetables in water and washed them well.
悲しい知らせを聞いて彼は深く心を沈めていった。
He was sunk in sorrow.