1. (noun)mistake, error, fault a wrongaction attributable to bad judgment or ignorance or inattention "he made a bad mistake"; "she was quick to point out my errors"; "I could understand his English in spite of his grammatical faults"
2. (noun)defect, fault, flaw an imperfection in an object or machine "a flaw caused the crystal to shatter"; "if there are any defects you should send it back to the manufacturer"
3. (noun)demerit, fault the quality of being inadequate or falling short of perfection "they discussed the merits and demerits of her novel"; "he knew his own faults much better than she did"
4. (noun)fault, faulting, geological fault, shift, fracture, break (geology) 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"; "he studied the faulting of the earth's crust"
Definition of 'fault'
