What is the meaning of the word "fail"?

Definitions:

be unable verb
- I fail to understand your motives
be unsuccessful verb
- Where do today's public schools fail?
become bankrupt or insolvent verb
- fail financially and close
fail to get a passing grade verb
- They studied hard but failed nevertheless.
fall short in what is expected verb
- They failed to meet their obligations.
judge unacceptable verb
- The teacher failed six students
prove insufficient verb
- The water supply for the town failed after a long drought