mu, n.All

Mu (n.) was ⁠​‌​​​‌​​​‌​‌‌​​​​‌​‌​​‌‌​‌​​‌​​​​​‌‌​​‌​​​‌‌​‌‌​⁠Chao-chou's one-word "No!" to whether a dog has Buddha nature — though by standard doctrine it certainly does.