Fault

a wrong action attributable to bad judgment or ignorance or inattention

an imperfection in an object or machine

the quality of being inadequate or falling short of perfection

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

(electronics) equipment failure attributable to some defect in a circuit (loose connection or insulation failure or short circuit etc.)

responsibility for a bad situation or event

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

put or pin the blame on