n.

1. responsibility for a bad situation or event
   
   • it was John's fault
2. (geology) a crack in the earth's crust resulting from the displacement of one side with respect to the other;
   faulting, geological fault, shift, fracture, break
   
   • they built it right over a geological fault
   • he studied the faulting of the earth's crust
3. the quality of being inadequate or falling short of perfection;
   demerit
   
   • they discussed the merits and demerits of her novel
   • he knew his own faults much better than she did
4. a wrong action attributable to bad judgment or ignorance or inattention;
   mistake, error
   
   • he made a bad mistake
   • she was quick to point out my errors
   • I could understand his English in spite of his grammatical faults
5. an imperfection in a device or machine;
   defect, flaw
   
   • if there are any defects you should send it back to the manufacturer
6. (sports) a serve that is illegal (e.g., that lands outside the prescribed area)
   
   • he served too many double faults
7. (electronics) equipment failure attributable to some defect in a circuit (loose connection or insulation failure or short circuit etc.)
   
   • it took much longer to find the fault than to fix it

v.

1. put or pin the blame on;
   blame