1. slang The choice to remain willfully ignorant of and disengaged from true reality. The term contrasts with "red pill," the choice to become aware of and engage with the real world, despite the pain or hardships that it may entail. The imagery is a reference to the 1999 film The Matrix, in which the main character is literally given a choice between a red pill, which will allow him to experience true reality for the first time, and a blue pill, which will result in him continuing to live as a prisoner in a simulated world. Taking that philosophy course was like choosing the red pill—I feel like my eyes have really been opened.

2. slang A man who rejects or remains oblivious to a conception of dominant masculinity rooted in misogyny and opposition to feminist ideals. The term contrasts with "red pill," a term for a man who holds or promotes such a conception of masculinity. (The origin of such imagery is detailed in Definition 1.) I can't believe Mike lets his girlfriend tell him what to do—what a blue pill.