是否

shìfǒu
  1. whether (or not)
  2. if
  3. is or isn't

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 否 fǒu
  1. to negate
  2. to deny
  3. not