cousies Share definition Flag A New Zealand-ism referring to one's cousins, or extended family. Can be used to include extended family, friends etc. Lets go grab the cousies first and then head up to Big T Takeaways for a mean feed. cousies by Graham 'Cous' Taylor July 4, 2006 0 0 Get merch Get the cousies mug. Buy Now — $32.95 See more merch