Used attributively before nouns to denote relation to a fault or malfunction.
Definitions
Relating to or caused by a fault, especially a geological or mechanical one; malfunctioning. Emergency teams monitored the fault sensors along the pipeline.
Exclamation used in tennis and similar sports to announce an invalid serve.
Definitions
Used by an umpire or observer to declare that a serve is invalid or out of bounds. "Fault!" shouted the umpire after the ball missed the service box.