Word Origin & History
loggerhead1588, "stupid person, blockhead," from dial. logger "heavy block of wood." Later it meant "a thick-headed iron tool" (1687), a type of cannon shot, a type of turtle (1657). Loggerheads "fighting, fisticuffs" is from 1680, but the exact notion is uncertain, perhaps it suggests the heavy tools used as
weapons. The phrase at loggerheads "in disagreement" is first recorded 1831.