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Probably you knew already the common meaning of “waffle” in British and American English. If you didn’t … this is a “waffle”:

A “waffle” is a type of pancake with a pattern of square dents in it, made in a waffle iron.

According to Random House Dictionary waffle with the British English meaning of talking idly, and foolishly without purpose is derived from waff (which means to bark or to yelp like a dog) and first appeared in print between 1695-1705.

Example sentences from the web:

• She waffled when asked what she thought of her sister’s new boyfriend.
• If you don’t know the answer, it’s no good just waffling (on) for pages and pages.

From a British newspaper clipping (1957):

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Remember that in American slang the meaning of “to waffle” is different.
Example sentences from the web:

• American voters waffled in 2000.
• He waffled on an important issue.
  [= to fail to make up one’s mind; to equivocate; to waver; to oscillate between options].