It means “The soul” in English.
“Kon” of the first character means “a soul” or “spilit”, and “Haku” of the second character means “a soul” or “spilit”, too.
“Konpaku” is words to appear in BLEACH, but it is existing Japanese not a coined word in BLEACH.
What is your favorite word in “BLEACH“? I’m waiting for a request.