The verb fail has 11 senses (first 5 from tagged texts)
1. (66) fail, neglect -- (fail to do something; leave something undone; "She failed to notice that her child was no longer in his crib"; "The secretary failed to call the customer and the company lost the account")
2. (33) fail, go wrong, miscarry -- (be unsuccessful; "Where do today's public schools fail?"; "The attempt to rescue the hostages failed miserably")
3. (5) fail, betray -- (disappoint, prove undependable to; abandon, forsake; "His sense of smell failed him this time"; "His strength finally failed him"; "His children failed him in the crisis")
4. (3) fail, go bad, give way, die, give out, conk out, go, break, break down -- (stop operating or functioning; "The engine finally went"; "The car died on the road"; "The bus we travelled in broke down on the way to town"; "The coffee maker broke"; "The engine failed on the way to town"; "her eyesight went after the accident")
5. (1) fail -- (be unable; "I fail to understand your motives")
6. fail -- (judge unacceptable; "The teacher failed six students")
7. fail, flunk, bomb, flush it -- (fail to get a passing grade; "She studied hard but failed nevertheless"; "Did I fail the test?")
8. fail -- (fall short in what is expected; "She failed in her obligations as a good daughter-in-law"; "We must not fail his obligation to the victims of the Holocaust")
9. fail -- (become bankrupt or insolvent; fail financially and close; "The toy company went bankrupt after the competition hired cheap Mexican labor"; "A number of banks failed that year")
10. fail, run out, give out -- (prove insufficient; "The water supply for the town failed after a long drought")
11. fail -- (get worse; "Her health is declining")