“CRACKBACK” is a valid word.

cracka long narrow opening
abackhaving the wind against the forward side of the sails
baccaan indehiscent fruit derived from a single ovary having one or many seeds within a fleshy wall or pericarp: e.g. grape; tomato; cranberry
kabar

backthe posterior part of a human (or animal) body from the neck to the end of the spine
crabdecapod having eyes on short stalks and a broad flattened carapace with a small abdomen folded under the thorax and pincers
barktough protective covering of the woody stems and roots of trees and other woody plants
rackframework for holding objects
kaka
carb
caca
arakany of various strong liquors distilled from the fermented sap of toddy palms or from fermented molasses
carkdisturb in mind or make uneasy or cause to be worried or alarmed
kbar

cara motor vehicle with four wheels; usually propelled by an internal combustion engine
bara room or establishment where alcoholic drinks are served over a counter
caba compartment at the front of a motor vehicle or locomotive where driver sits
braan undergarment worn by women to support their breasts
ark(Judaism) sacred chest where the ancient Hebrews kept the two tablets containing the Ten Commandments
arcelectrical conduction through a gas in an applied electric field
baathe cry made by sheep
abaa loose sleeveless outer garment made from aba cloth; worn by Arabs
kab
arbsomeone who engages in arbitrage (who purchases securities in one market for immediate resale in another in the hope of profiting from the price differential)

baa soft silvery metallic element of the alkali earth group; found in barite
ara colorless and odorless inert gas; one of the six inert gases; comprises approximately 1% of the earth's atmosphere
kaunknown god; an epithet of Prajapati and Brahma
aaa dry form of lava resembling clinkers
aba bachelor's degree in arts and sciences

CRACKBACK