排空

páikōng
  1. to drain out; to empty
  2. to discharge (waste gas) into the air
  3. to soar up into the sky

CEDICT

Entry Composition

1 排 pái
  1. a row
  2. a line
  3. to set in order
  4. to arrange
  5. to line up
  6. to eliminate
  7. to drain
  8. to push open
  9. platoon
  10. raft
  11. classifier for lines, rows etc
2 空 kōng
  1. empty
  2. air
  3. sky
  4. in vain