So, you're the Weeb who decided to look up what nandayo means on English, and stupidly found yourself at Urban Dictionary. Lucky for you, I have a Weeb brother who knows these things. You two would get along well. Anyway, nandayo means what. You are probably thinking, "b-but, iLoveEthanDolanBecauseHe'sTheB~sensei! Nani means what!!! You can't possibly be right! BUT, we young Weebs, nandayo is like when your little anime buddies are like "He used the ultimate power!! NANDAYO?!?!?!" So yeah. Nandayo is nani with surprised expressions. 🤤. Goodbye.