1
to sink;to go under;to submerge
まるで、沈む船から逃げるネズミみたいね。
It's just like rats leaving a sinking ship.
2
to go down (e.g. sun);to set;to descend
太陽が水平線の下に沈んだ。
The sun sank below the horizon.
3
to feel depressed;to become subdued;to become somber