oofadoofa
I apologise, then, but I’d genuinely never come across it up until a year or two or go. There must be a better one to use for whatever point it is making?
There isn't - the movie 'Gaslight' was about an abusive husband (actually a thief and murderer) systematically lying to his wife in many small ways with the intention of inflicting psychological harm on her and making her doubt her perception of reality. (Ultimately his aim was getting his hands on some valuable jewels he knew were somewhere in the house, but this is extraneous to the usual reason for this form of psychological abuse, which is to exert control).
'Gaslighting' is perfect because it harkens to the dynamic as well as the origin of the phrase, with the gaslight flickering, dimming and brightening serving also as a metaphor suggesting the gradual removal of the ability to see what is all around you and to trust in the reality of what you see and know in your surroundings. In the movie, the husband manipulated the wife's perception of reality in various ways including dismissing her perception of the lights dimming or flickering when he turned on the lights in the attic to search for the hidden jewels.
This is from Wikipedia:
In 2006, film critic Emanuel Levy discussed the film noir aspects of the film:
<span class="italic">"A thriller soaked in paranoia, Gaslight is a period films [sic] noir that, like Hitchcock's The Lodger and Hangover Square, is set in the Edwardian age. It's interesting to speculate about the prominence of a film cycle in the 1940s that can be described as 'Don't Trust Your Husband'. It began with three Hitchcock films: Rebecca (1940), Suspicion (1941), and Shadow of a Doubt (1943), and continued with Gaslight and Jane Eyre (both in 1944), Dragonwyck (1945), Notorious and The Spiral Staircase (both 1946), The Two Mrs. Carrolls (1947), and Sorry, Wrong Number and Sleep, My Love (both 1948). All of these films use the noir visual vocabulary and share the same premise and narrative structure: The life of a rich, sheltered woman is threatened by an older, deranged man, often her husband. In all of them, the house, usually a symbol of sheltered security in Hollywood movies, becomes a trap of terror."</span>
en.wikipedia.org/wiki/Gaslight_(1944_film)#Plot