K-B-D
K-B-D (Hebrew כבד; East Semitic K-B-T) is a triliteral Semitic root with the common meaning of to "be heavy", and thence "be important; honour, majesty, glory".
The basic noun formed from the root means "liver", "interior", "soul" in most Semitic languages.
The Akkadian word for liver is spelled with the sumerogram 𒂂 , transliterated kabtu; the Ugaritic cognate is spelled 𐎋𐎁𐎄 kbd.
There is a wide range of uses for kbd as a noun among the Semitic languages. It can be used literally to denote the organ of the "liver", or more figuratively to refer to the "interior of the body", seen as being "the seat of human will and emotions."
Akkadian kbt
In Akkadian, an East Semitic language which has the kbt form of the root, kabattu is used to denote the realm of "violent emotions" and "blind passions".
According to Wolfgang Heimpel in Letters to the King of Mari, the Babylonian root kbt was vocalized as kbd in Mari, and an adjectival derivation of the root appears in Mari inscriptions that record royal correspondences. Heimpel translated its meaning as "heavy", as in the following exceprt: "The troops are well. The tablets are heavy for the messengers whom Ibal-Pi-El is sending, and so my mail to you is not regular."