Malfunction (FTF / FTE)
Also known as: stoppage
Any interruption in a firearm's cycle — common types include failure to feed, failure to fire, failure to extract, and the 'stovepipe'.
A malfunction (or stoppage) is any failure of the gun to fire or cycle correctly. The common abbreviations: FTF can mean failure to feed (a round doesn't chamber) or failure to fire (the round doesn't ignite); FTE means failure to extract or eject (the spent case stays in or doesn't clear). A 'stovepipe' is a spent case caught vertically in the ejection port.
Most malfunctions are cleared with the immediate-action 'tap, rack, bang' drill: tap the magazine to seat it, rack the slide to clear and re-feed, and reassess. Causes range from bad ammo and worn magazines to a dirty gun or shooter-induced limp-wristing. Practicing malfunction clearance is a core defensive skill.