My nine Share definition Flag Phrase used to describe a friend or comrade. Someone with whom one has had a long standing relationship with; used to describe brotherly and philanthropic persons. What's up "my nine"? Want to grab a bite to eat?What it do "my nine"? You tryna get turnt tonight? My nine by smadamal August 10, 2016 0 0 Get merch Get the My nine mug. Buy Now — $32.95 See more merch