Wibble is certainly rare, but it is in some dictionaries. It's been around since the 19th century, meaning to wobble. In this sense people often say "wibble and wobble", but
wibble can appear on its own, as in this quote from the
Spectator in May 2022:
But equally, I want a tart from which I can cut clean slices that wibble onto the plate, holding their shape, from the fluted pastry to the perfect, tapering nose.
I think it has the sense here of a wobble that isn't very wobbly.
The other meaning of the word is to speak or write in a vague and/or wordy manner, often as
wibble on. This is where Blackadder is relevant. The word was used in the show as something meaningless, that Blackadder could repeatedly utter so as to be found insane, and escape from the war. (Spoiler alert: it didn't work.) It's possible that this is what led to
wibble being used for inane chatter. At any rate, the OED has the Blackadder usage as pre-dating any other examples. However, Wiktionary mentions a comic strip character called Roger Irrelevant, who used to say "wibble wibble".
At any rate, the word has entered the language, mainly in Britain. A 2022 example from the road.cc website:
Different tyre makers have different favoured ingredients that allegedly have certain effects, but determining what's marketing wibble and what's real is tricky.
I'll add
wibble,
wibbling and
wibbled as rare words.
