Definition of dead-on:
(adj) :
(usually not comparable) No longer living; deceased. (Also used as a noun.)
(adj) :
(usually not comparable) Devoid of living things; barren.
(adj) :
(hyperbolic) Figuratively, not alive; lacking life.
(adj) :
(of another person) So hated or offensive as to be absolutely shunned, ignored, or ostracized.
(adj) :
(literal or hyperbolic) Doomed; marked for death; as good as dead.
(adj) :
Without emotion; impassive.