brand spanking new

[Bobjex]

Where on earth does the 'brand' and especially 'spanking' come from in 'brand spanking new' ??

[Quizmonster]

The 'brand' part comes from the same source as the idea of a 'brand' being a burning torch, as in the word 'firebrand'. The concept is that the thing concerned is so new it's as if it had just come from the furnace or blacksmith's forge. Shakespeare actually used the phrase 'fire new' in the same context.

'Spanking' is probably related to the Danish word 'spanke' which means to 'strut'. So, if something is 'spanking' it means it's showy and especially fine.