SQRT((NAF)^4) Share definition Flag a long sleeved life vest used as a jacket. see also PFD, NAF NAF or (NAF)^2 You have a NAF NAF! You are a homophobic hetrosexual. SQRT((NAF)^4) by PHISH November 24, 2003 0 0 Get merch Get the SQRT((NAF)^4) mug. Buy Now — $32.95 See more merch