HoH is a general word for kill. ghab means kill as a result of hunting (thus the hunt was a successful one) or when the killing is the result of a planned-out process.

KGT p. 27: The word ghab, however, which refers to any chunk of the midsection of an animal, has slightly varying meanings depending on region. In most of the empire, including the First City, ghab is rather inclusive: basically,whatever was chopped off the animal as a single piece, with or without bones or internal organs. KGT p. 87. Large animals are usually chopped into pieces, sometimes with attention paid to which piece is which (thus a tIq ["heart"] might be served as a dish in its own right), sometimes not (the ghab, for example, is just a chunk of the midsection of an animal, including any organs that may have remained attached after the carving).