Biter comes from bite (Old English bītan 'to bite') + agentive -er; the archaic sense 'cheat' comes from bite meaning 'to swindle, take in'. The historical trail runs through bītan in Old English and -er in Old English. Morphologically, biter is transparent: it draws on bite (Old English bītan 'to bite') + agentive -er. Used as a noun, biter now means "one that bites; also archaically a cheat or deceiver", so the present definition can be read against the older forms and meanings. The same lexical family is also visible in related forms such as bite, bait, and bitter. The modern word remains analyzable through its parts, which makes the semantic connection unusually direct.