Definitions of fault:

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

  Example: "He served too many double faults"

• noun:   responsibility for a bad situation or event

  Example: "It was John's fault"

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

  Example: "It took much longer to find the fault than to fix it"

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

  Example: "They built it right over a geological fault"

• noun:   the quality of being inadequate or falling short of perfection

  Example: "He knew his own faults much better than she did"

• noun:   an imperfection in a device or machine
• noun:   a wrong action attributable to bad judgment or ignorance or inattention

  Example: "I could understand his English in spite of his grammatical faults"

• verb:   put or pin the blame on