是不是

shìbùshì
  1. is or isn't
  2. yes or no
  3. whether or not

CEDICT

Entry Composition

=1 是 shì
  1. to be (followed by substantives only)
  2. correct; right; true
  3. (respectful acknowledgement of a command) very well
  4. (adverb for emphatic assertion)
=1 是 shì variant of 是 shì
=2 不是 bùshì
  1. no
  2. is not
  3. not
=2 不是 bùshi fault; blame