What is another term for "not working properly"?

When something is not working properly, several alternative terms and phrases can be used depending on the specific context and whether you are referring to a mechanical device, a software application, or a general system. Common synonyms include malfunctioning, misbehaving, acting up, glitching, failing, breaking down, stuttering, faltering, and performing below standard. In technical contexts, professionals might describe a malfunctioning component as experiencing a fault, an anomaly, a degradation in performance, or an operational error. Colloquially, people often say that a device is on the blink, playing up, out of whack, or simply busted. Each of these terms carries a slightly different nuance; for example, "glitching" often implies a temporary electronic or software hiccup, whereas "malfunctioning" or "failing" typically suggests a deeper mechanical or structural issue that requires troubleshooting or professional repair.

Professional synonyms and technical terms for something that is not working properly include malfunctioning, operating sub-optimally, experiencing performance degradation, misbehaving, throwing faults, running erratically, or operating out of specification. In engineering and mechanics, when a component fails to meet its exact operational benchmarks while still running, technicians classify it as suffering from an intermittent performance defect or parametric failure requiring immediate calibration.