noggin

Etymology

Of uncertain origin. It first appears around 1588, and turns up in 1600s publications (for instance in The Tincker of Turvey) in several forms: the still-current Irish English naggin, the rarer older Irish, Scottish and Northern English noggan, used by Jonathan Swift, and the Wexford form nuggeen. Tomás S. Ó Máille and some older dictionaries such as Skeat's trace it to Irish naigín, cnaigín, from cnagaire, cnag, but the Oxford English Dictionary argues instead that Irish naigín and Scottish Gaelic noigean derive from English. Compare nog.