Very obscure. Google returns only 22,200,000 results for the word “gaslight” and “gaslighting” has its own Wiki entry (note the photo is from the film):
The word traces to the stage play that the movie above is based on, but the movie (which garnered seven Oscar nominations, including a win for Best Actress by Ingrid Bergman) is credited with its widespread adoption.
So, an obscure reference for a generous interpretation of the term obscure.