accountableness comes from accountable + -ness, from account, from Old French aconter ('to reckon'), from a- ('to') + conter ('to count'), from Latin computāre ('to compute'). Morphologically, the word is transparent: -ness is attached to the older base named in the history, so the modern form packages an inherited or borrowed stem inside a later English derivative. In modern use, the noun sense is "the quality of being answerable or liable for one's actions", which keeps the etymology connected to the word's present dictionary value rather than treating it as a merely historical label. The wider word family includes related English forms such as accountable, accountability, account, showing how the same base continues to support neighboring English vocabulary. The principal historical forms in the chain include Latin computāre, Latin putāre, which anchor the explanation in named linguistic material.