tallywhacker

1. Latintalea“stick, twig”
2. Medieval Latintallia
3. Old Frenchtaillee
4. Anglo-Normantallie
5. Middle Englishtaly“a tally stick”
6. Englishtallywhacker

Uncertain. Possibly from tally (“mate, counterpart”), from Middle English taly (“a tally stick”), from Anglo-Norman tallie, Old French taillee, taillie, from Medieval Latin tallia, talia, taillia, from Latin talea (“stick, twig”), or alternatively from tail, + wag, likely influenced by whack, + -er. Compare tallywag, an eighteenth century dialect term meaning “penis”. Attested as tallywhacker or tallywacker since the twentieth century.

More words from Middle English, Anglo-Norman, Old French