Definition of: fault

(fôlt) noun
1. A slight offense; failure; negligence.
2. Whatever impairs excellence; an imperfection or defect in a person or thing; failure; blemish.
3. Geol. a A dislocation of a stratum or vein of ore which breaks its continuity. b A displacement or break in the continuity of rock masses, caused by disturbances of the earth's crust and resulting in a wide variety of surface features.
4. A missing or losing of the trail or scent: said of hunting dogs.
5. Electr. A deflection or leak in a current, due to abnormal connection of circuits or defective insulation of a conductor.
6. In tennis, rackets, etc., a failure by the server to drive the ball into the proper part of his opponent's court; also, a failure by the server to have both feet on the ground behind the service line in serving: usually called foot fault.
7. Obs. Default; lack. See synonyms under BLEMISH, ERROR, OFFENSE.
—at fault
1. In the wrong.
2. Worthy of blame.
3. Off the scent.
4. Hence, at a loss; in a quandary.
—in fault Blameworthy.
—to a fault Exceedingly; excessively: generous to a fault.
—v.t.
1. Rare To find fault with; blame.
2. Geol. To cause a fault in.
—v.i.
3. Archaic To commit a fault; err.
4. Geol. To crack or fracture so as to produce a fault. [<OF faute, ult. <L fallere deceive]
—fault′·ful·ly adverb
—fault′ful·ness noun