adv. phr. So very well that it is in a way bad; to the point of being rather foolish; too well; too much. Aunt May wants everything in her house to be exactly right; she is neat to a fault. Mary acts her part to a fault. John carries thoroughness to a fault; he spends many hours writing his reports.
TO A FAULT
Meaning of TO A FAULT in English
American idioms English vocabulary. Английский словарь американских идиом. 2012