Feel like everyone has already weighed in on this but to me it's how people *use* it. The internet has ruined it through over- and misuse like it's ruined every other term. Gaslighting is a specific type of lying, though, not fully interchangeable. https://twitter.com/mattyglesias/status/1192099133261336578 …
It's a type of psychological torture. Unfortunately it exists by degrees and you find it in inconvenient places so in practice most people ignore it, cover it up or accuse their victim of doing it.