Balderdash \BAWL-der-dash\ , noun;
1. Senseless, stupid, or exaggerated talk or writing; nonsense
2. Archaic: A muddled mixture of liquors
The origin of balderdash is unknown, but it dates to around 1590 with the archaic definition given above. The meaning "senseless jumble of words" dates to the 1670's.
If you split the word into it's formative parts, balder + dash, you could guess at the origins.
Balder could be a cognate with Danish balder ("noise, clatter"), which is related to boulder.
Dash dates to the 1300's and also comes from a Scandinavian source word. It's meaning has always implied a sense of moving quickly, including a definition of "to write hurriedly" in the early 1700's.
So thinking of the original definition, "a muddled mixture of liquors" and a guessed compound of "noise, clatter" + "move quickly," it could make sense if you consider that state of a party when muddled mixtures of liquor flow freely. It could be kind of a stretch though.
Today's word and the first definition were both taken from Dictionary.com's 'Word of the Day' for Monday, April 11
Etymologies come from the Oxford English Dictionary and/or Etymonline.com