gnaw

The Old English verb gnagan meant to bite or chew persistently, especially with the front teeth. It appears in texts as early as the 9th century. The form descends without interruption from Proto-Germanic gnaganą, shared by a cluster of northern European tongues. That deep root may connect to a Proto-Indo-European base meaning to scrape or rub.

Old Norse had the near-identical gnaga, and Old High German had gnagan — the same sound, the same image of rodent against wood or bone. The doubled consonant at the start, that gn-, was once fully pronounced in Old English, both sounds voiced. By the 14th century, Middle English gnawen had softened the cluster's opening in speech while keeping it in the written form.

The silent g in gnaw today is a fossil of that earlier pronunciation. It is one of English's many spelling-pronunciation gaps, preserved by decades of orthographic conservatism after printers fixed the written forms. By Shakespeare's time the g had gone silent in educated southern speech, yet the letter stayed because compositors worked from older manuscripts. The printed page slowed the language down, as it always does.

Gnaw took on figurative weight early, appearing in religious texts as the action of sin or guilt on the soul. To gnaw at a problem, at a conscience, at a relationship — the metaphor extends naturally from the image of slow persistent erosion. The image needed no explanation; anyone who had watched a dog with a bone already understood it.