TACNAYN Share definition Flag Noun or Verb. N: The popular video of backwards nyan-cat audio and visuals. V: To watch TACNAYN. Yo man, I love TACNAYN!Yo man, I tacnayn'd 6 hours yesterday! It's like NyanCat! TACNAYN by IAmCow69 July 1, 2011 0 0 Get merch Get the TACNAYN mug. Buy Now — $32.95 See more merch