不一

bùyī
  1. to vary
  2. to differ

CEDICT

Entry Composition

1 不 bù
  1. no; not so
  2. (bound form) not; un-
2 一 yī
  1. one
  2. single
  3. a (article)
  4. as soon as
  5. entire; whole; all; throughout
  6. "one" radical in Chinese characters (Kangxi radical 1)
  7. also pr. yāo for greater clarity when spelling out numbers digit by digit