Go Off At Score Meaning

(idiomatic) Of a horse, to break suddenly into a gallop; of a person, suddenly to say or do something impetuous.

Example: 1888: Bremmil went off at score after the baby's death and the general discomfort that followed, and Mrs Hauksbee annexed him. — Rudyard Kipling, ‘Three and—an Extra’, Plain Tales from the Hills (Folio Society 2005, p. 12)