Authors' Note: The disparaging term gobbledegook was first used in 1944 by a Texas politician named Maverick (scion of the original staunchly independent thinker). Its meaning — pompous, overinflated language — gave rise a few year later to the equivalent bafflegab. These expressions, employing repetition of sounds, have a musical and amusing quality, as do their venerable synonyms --hogwash, poppycock, balderdash, bunkum and tommyrot, but only their close cousin claptrap (alternately clap-trap) -- would qualify as a reduplication.
fuddle-duddle: an infrequently used (re)duplication, voiced dismissively in dealing with opinions that the speaker rejects.
In 1971 Prime Minister Pierre Trudeau, father of current PM Justin Trudeau, unleashed a minor scandal by using unparliamentary language in the Canadian House of Commons. A portion of the ensuing brouhaha, deftly sidestepped by Trudeau, revolved around whether he had actually spoken or merely mouthed the inappropriate words.
rubba: rubber (American slang for condom), with typical non-rhotic pronunciation
hubba-hubba: intriguing (re)duplication, presumably originating in the US a century ago; an expression of approval voiced by males when viewing a sexually attractive chick
Be prepared, as a plebe, for this blow:
Hoi polloi (Greek) meant every John Doe,
Riff-raff, masses (unwashed);
But that use has been quashed,
By the upper crust now, you should know.
Authors' Note: The (re)duplication hoi polloi derives from the ancient Greek term for the many. This expression, tinged with disparagement, like its close cousin riff-raff, was used in English for some time. In a recent inexplicable twist, as described by speedysnail, hoi polloi has come to be used, in some circumstances, to mean the exact opposite.
SONGS about REDUPLICATIONS!