可是

kěshì
  1. but; however
  2. (used for emphasis) indeed

CEDICT

Entry Composition

1 可 kě
  1. (prefix) can; may; able to; -able
  2. to approve; to permit
  3. to suit
  4. (particle used for emphasis) certainly; very
  5. but; however
=2 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)
=2 是 shì variant of 是 shì