1. Be unsuccessful
   "Where do today's public schools fail?"; "The attempt to rescue the hostages failed miserably";
   - go wrong, miscarry
    
2. Not do something; leave something undone
   "The secretary failed to call the customer and the company lost the account"; "She failed to notice that her child was no longer in his crib";
   - neglect
    
3. 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"
    
4. Prove insufficient
   "The water supply for the town failed after a long drought";
   - run out, give out
    
5. Be unable
   "I fail to understand your motives"
    
6. Be unsuccessful in a test, get lower than the passing grade
   "Did I fail the test?"; "She studied hard but failed nevertheless";
   - flunk [N. Amer, informal], bomb [informal]
    
7. Stop operating or functioning
   "The engine failed on the way to town";
   - go bad, give way, die, give out, conk out [informal], go, break, break down, pack up [Brit, informal], give up the ghost [informal]
    
8. Disappoint, prove undependable to; abandon, forsake
   "His strength finally failed him"; "His children failed him in the crisis"; "His sense of smell failed him this time";
   - betray
    
9. Become bankrupt or insolvent; fail financially and close
   "A number of banks failed that year"
    
10. Judge unacceptable
    "The teacher failed six students"
     
11. Deteriorate
    "The patient's condition failed rapidly overnight"

1. A non-passing grade in an examination or test
   "He received a fail in his chemistry exam"

Derived forms: fails, failed, failing

Type of: act, alter, cease, change, decline, disappoint, end, evaluate, finish, judge, let down, move, pass judgment, stop, terminate, vary, worsen

Antonym: bring home the bacon [informal], bring off, pass

Encyclopedia: Fail, Viseu