drop out—
1. leave a school, etc. before the end of the course:
- He has dropped out, and won’t attend college any more.
2. (coll.) withdraw (from an undertaking):
- You can drop out from the rat race, hoping that you can make it on your own.
3. come out:
- As she picked up the envelope, a key dropped out.
fall out—
1. (Military) leave the ranks:
- At the end of the parade, the battalion fell out.
2. quarrel:
- We’re not going to fall out over this, are we?
3. come to pass; happen:
- It fell out that the men were not needed.
4. = drop out 3:
- A little roll of dollar-notes fell out upon the ground.