Not achieving very much. The clearest use is about time and effort: an unproductive meeting, an unproductive morning, an unproductive discussion that went round and round and settled nothing. The complaint is not that people were lazy but that the work did not turn into anything — you can be busy all day and still be unproductive, and that gap is exactly what the word points at. It also has a plainer, more physical use: unproductive land or unproductive soil grows little, an unproductive oil well yields little, an unproductive factory makes little for what it costs. Doctors use it in a phrase worth knowing on its own, an unproductive cough — a dry cough that brings nothing up. The word is neutral in tone, more like a measurement than an attack, which makes it useful at work: calling a meeting unproductive criticises the meeting, while calling your colleague unproductive criticises them, so people reach for it when they want to complain about a situation without blaming a person. It is mildly formal and very common in business English.