Definition of red pill:
(n) :
(informal) Something that, in the view of the speaker or writer, enables or compels a person to overcome illusion and perceive harsher reality.
(v) :
(transitive, intransitive, informal) To enable a person to overcome (what the speaker or writer believes to be) illusion and thus to perceive harsher reality.
(n) :
(slang) Something that causes someone to believe in gynocentrism in modern society.
(v) :
(transitive, intransitive, slang) To cause someone to believe in gynocentrism in modern society.
(n) :
(slang, by extension) The subculture of men who share a belief in the gynocentrism of modern society; manosphere.
(n) :
Used other than figuratively or idiomatically: see red, pill.