Bait offers a compact lesson in Germanic word formation. It derives from Old Norse beita, the causative form of bíta ("to bite"). In Germanic languages, causative verbs were formed by modifying the vowel of a base verb: bíta ("to bite") became beita ("to cause to bite, to make bite"). Thus bait is, at its etymological core, "that which causes biting" — the food that makes the fish bite the hook. The corresponding noun beit meant "food" or "pasture," the sustenance that keeps animals alive by enabling them to bite and chew.
The Proto-Germanic root *baitō ("food, pasture") descends from *baitijaną ("to cause to bite"), itself from *bītaną ("to bite"), all ultimately from the Proto-Indo-European root *bʰeyd- ("to split, bite"). This root family gives English not only "bait" and "bite" but also "bitter" (that which bites the tongue) and "beetle" (the biting insect, from Old English bītan).
The word entered English during the period of heavy Norse influence on the language, particularly in northern and eastern England where Scandinavian settlement was densest. Fishing and hunting vocabulary was especially susceptible to Norse influence, as these were shared daily activities between Anglo-Saxon and Norse-speaking populations. Other Norse-derived hunting terms that entered English include "ransack," "slaughter," and "steak" — the last of which also derives from a word meaning "to stick" or "to cut."
The darker history of "bait" involves the blood sports of medieval and early modern Europe. Bear-baiting, bull-baiting, and badger-baiting involved chaining an animal to a stake and releasing dogs to attack it. "To bait" thus acquired the sense of tormenting or provoking, a meaning that persists in "to bait someone" (to deliberately provoke). These sports were enormously popular — Henry VIII had a royal bear pit, and Elizabethan Bankside hosted baiting arenas
In modern usage, bait has extended into the digital world. "Clickbait" — content designed to lure clicks through sensational headlines — recapitulates the word's oldest logic: offering something enticing to trigger a bite.