"brand spanking new" - is this correct grammar & polite way to say?

I saw an add saying "This iphone is brand spanking new" which sound like "brand * new".

I am not sure if this word has correct grammar + polite (ie people use it without any bad or joke meaning)

Solution 1:

There's no connection to spank = slap, smack [with the open hand]. OED says of spanking...

Etymology: Of doubtful origin. Compare Danish (and North Frisian) spanke to strut.

Their first citation for sense 1: Very big, large, or fine; exceptionally good in some respect, freq. with implication of showiness or smartness. is 1666.

The more specific sense 5: Used as adv. Very, exceedingly; esp. as spanking new, brand-new is first recorded in 1886.

Note that all these adjectival/adverbial usages are designated Chiefly dial. and colloq. by OED.

EDIT: This NGram confirmed my suspicion that a significant proportion of all instances of the very common spanking new occur as brand spanking new. But by far the more common phrasing is brand new - extant 1570, original metaphoric allusion unknown to most speakers today. It seems a bit odd that we can just slot spanking into the middle of a well-established set phrase like that.

Possibly, in the minds of some speakers spanking has connotations of smacking, striking[ly], but it's really just a syntactic element (function word?) whose sole purpose is to intensify an adjacent semantic element that actually has "meaning" (in this case, either the adjective new, or the set phrase brand new, depending how you see it).

Although OED offers very, exceedingly as "definitions/synonyms", idiomatically you can't just substitute either of those in brand ???? new. The only syntactically/semantically compatible word I can come up with is brand fucking new (which though vulgar is perfectly valid grammatically).

To me, the usage brand spanking new seems to reflect that of fucking and abso-bloody-lutely i.e. - an intensifier is "infixed" into a single word or set phrase.

I was therefore gratified to find my guess for a credible usage was abso-spanking-lutely spot on! There's a couple of dozen people who've also noticed that relatively uncommon syntactic flexibility allowing "infixed intensifier" usage - without the potential drawbacks of vulgar fucking, bloody.