Well, if you're disagreeing with someone who cannot conceive that they _might_ be wrong, then to them you _are_ gaslighting them. Even though they're just wrong and refusing to engage.
No. Because only if they _could_ conceive that they were wrong, would you be gaslighting them. You have to succeed at making them doubt themselves for it to be gaslighting.
Fair counterpoint. But gaslighting would still have to be a continued effort over a long period of time. If it's just one conversation/argument, then that still isn't gaslighting. Or to put it another way: the distinction would be are they persistently (and subversively) trying to change your thoughts on the matter for their own personal gain, or did they just express disagreement?
It would be nice if that was as far as it drifted. I've seen it used as a synonym for "disagreeing [with me]" and "mistaken".