Sigma Males refers to a supposed classification for men who are successful and popular, but also silent and rebellious, a type of man who likes to "play by his own rules." In most analyses, they are considered "equal" to Alphas on the hierarchy but live outside of the hierarchy by choice. John Wick has often been cited as a popular example of a Sigma Male. After the classification was discovered by Twitter user @LilySimpson1312, it was mocked online by people expressing distaste for the greek alphabet system of male classification.