The term ONE SKILLED AT DEAD RECKONING can be summarized as a Coroner, which is a seven letter word. A Coroner is a public official who investigates deaths that occur under suspicious or unknown circumstances. They are responsible for determining the cause of death and may also be involved in the identification of the deceased. Coroners are often SKILLED AT DEAD RECKONING, which is the process of estimating ONE's current position based on a previously determined position, direction, and speed.