不成

bùchéng
  1. won't do
  2. unable to
  3. (at the end of a rhetorical question) can that be?

CEDICT

Entry Composition

1 不 bù
  1. no; not so
  2. (bound form) not; un-
2 成 chéng
  1. to succeed
  2. to finish
  3. to complete
  4. to accomplish
  5. to become
  6. to turn into
  7. to be all right
  8. OK!
  9. one tenth