Fall
Sinking, Surrender
noun, verbal noun
If you fall during a cave in you'll fall along with everything around you. And that sinking feeling in your stomach is because... I mean, well you ARE sinking into the ground.
This is a jukugo word that uses the on'yomi readings of the kanji. You should be able to read this on your own.
トヨタが世界一から陥落したのは何故だと思いますか。
Why do you think that Toyota fell from being the best in the world?