Faulty/ˈfɔːlti/ Definition 1 of 2Pro Tip 1/3Product Problems Use 'faulty' when talking about items that don't work as they should. The heater is faulty and won't turn on. Pro Tip 2/3Industry Jargon 'Faulty' is commonly used in manufacturing and retail when discussing defective goods. We received several complaints about faulty appliances. Pro Tip 3/3Subtle Blame Describing something as 'faulty' subtly implies that there is a responsible party for the defect. The accident was caused by a faulty brake system.