dead-on

The compound 'dead-on' is a relatively modern English formation, originating in the late 19th to early 20th century. The word 'dead' evolved from its Old English sense of 'lifeless' to develop figurative meanings of 'absolute', 'complete', or 'unqualified', as seen in phrases like 'dead center' or 'dead stop'. Combined with the preposition 'on', which denotes position or alignment, the phrase literally means 'completely on target'. This logic perfectly captures the modern abstract meaning of precise accuracy, whether describing a physical shot, a prediction, or an assessment.

Structure: dead (complete) + on (position) dead (from Old English dēad, meaning 'lifeless', used here in the sense of 'absolute' or 'complete'); on (from Old English on, an, meaning 'in, into, toward, on', indicating position or alignment)