fault

a wrong action attributable to bad judgment or ignorance or inattention

“I could understand his English in spite of his grammatical faults”

an imperfection in an object or machine

the quality of being inadequate or falling short of perfection

“he knew his own faults much better than she did”

a crack in the earth's crust resulting from the displacement of one side with respect to the other

“they built it right over a geological fault”

put or pin the blame on

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”

responsibility for a bad situation or event

“it was John's fault”

a serve that is illegal (e.g., that lands outside the prescribed area)

“he served too many double faults”