dog eat dog

Ruthless competition. Although this saying dates from the sixteenth century, it was at first put very reluctantly, because a much older observation has it that dog does not eat dog (a Latin proverb). Thus Thomas Fuller (Gnomologia, 1732) pointed out that “dogs are hard drove, when they eat dogs.” The transfer to human affairs had it otherwise, however. “Dog won’t eat dog, but men will eat each other up like cannibals,” wrote C. H. Spurgeon (John Ploughman, 1869).