I would add another observation to this discussion. Nano has quite adequately discussed the naughty resonance, at least in American ears, of YumNuts. The question of the meanings swirling around doughnuts has come up. I worked with an individual whose first language was not English, who delightedly persisted in pronouncing the word doughnuts as ´Dog-Nuts´, thus making a salacious commentary on some of the irrationalities of spelling in the English language.
As to the rest of this discussion, I am fairly certain General Anthony McAuliffe, of the famous defense of Bastogne during the Battle of the Bulge would have been able to illuminate various shades of meaning. I am not certain ´numbnuts´ was current slang during WWII, but McAuliffe would´ve twigged its usage as apt in describing the German Commander´s inability to understand his one word reply to a request for surrender.

Bob
