the practice of psychologically manipulating someone into questioning their own sanity, memory, or powers of reasoning

he said he was the victim of gaslighting

gaslighting is an insidious technique of deception and psychological manipulation

manipulate (someone) using psychological methods into questioning their own sanity, memory, or powers of reasoning

in the first episode, Karen Valentine is being gaslighted by her husband

we are being gaslit about our health on a grand scale by these people