Spyware is software that gets onto your computer or phone and quietly watches what you do — which websites you open, what you search for, sometimes what you type — and sends that information away to someone else, usually without you ever agreeing to it. Advertising companies use it to decide which ads to push at you. Nastier kinds go after passwords and bank details. It normally arrives hidden inside something else: a free program you downloaded, an attachment you opened, a browser add-on that looked useful. That hiding is what makes it spyware rather than an honest tracking tool — it is the secrecy, not the watching alone. The word is uncountable, like water: you say "some spyware" or "a piece of spyware", never "a spyware" or "two spywares". It sits in the same family of words as malware (bad software in general), adware, and ransomware, and you will hear it in any conversation about keeping a computer safe.