Fail

Fail = (1) Not do something; leave something undone: ‘She failed to notice that her child was no longer in his crib.’ (2) Be unsuccessful: ‘The attempt to rescue the bus failed miserably.’ (3) Stop functioning or operating: ‘The engine failed on the way to town.’ (4) Be unable: ‘I fail to understand your feelings.’ (5) Prove insufficient: ‘The water supply for the town failed after a long drought.’