Chuck a wobbly is Australian slang for someone throwing a tantrum, and I like it because it invokes amusing imagery.
I'm not certain of its origins however. I can see how it may be equivalent to the similar-meaning idiom "throw a fit", where "chuck" is also Australian slang for "throw", but I can't be certain of what "wobbly" is supposed to mean. It's more difficult to nail down because as far as I know, "wobbly" isn't used in other phrases in Australian slang.
Chucking a wobbly comes from throw a wobbly and wobbly refers to a fit of anger, possibly suggesting the person is mentally unbalanced.
The 1994 Shorter Slang Dictionary (Partridge, Beale, Fergusson) says:
throw a wobbly to become angry, agitated or mentally unbalanced; to behave irrationally or unpredictably. Later 20th century.
The 2008 New Partridge Dictionary of Slang and Unconventional English says:
wobbly noun a fit of anger UK, 1977. < throw a wobbly to have a fit of bad temper or anger NEW ZEALAND, 1984
The OED says:
to throw a wobbly : to lose one's self-control in a fit of nerves, panic, temperament, annoyance, or the like; also, to act in an unexpected way, causing surprise or consternation.
Their first quotation is from the Brisbane Telegraph on 13 April 1977.
I found the phrase slightly earlier in the Australian Trove archive of newspapers in The Canberra Times of 12 March 1977:
The story begins with Howard Beale, a nationally-broadcast news commentator, throwing a wobbly on camera and getting fired.
It shows up in a 1964 Google Books snippet of The Watersiders by Michael Davis:
They were laying down long planks at odd angles from the square as though about to participate in some peculiar rite. "What's the matter, mate? You look queer. Ain't going to throw a wobbly, are you?"
Google Books snippets are sometimes wrong, but the author, title and year seem correct and it was published in Australia so it's plausible.
Another Google Books snippet is from the 1972 Parliamentary Debates of New Zealand:
Mr Moyle — Perhaps he will throw a plum at them. Mr TIZARD — He can throw a plum, or he can throw a "wobbly", which is more in keeping with the Minister. He complained that the Opposition did not congratulate the Government and the ...
Searching for 1972 brings up correct-looking results. Furthermore, Colin Moyle was an MP from 1963-1977 (and 1981-1990), as was Bob Tizard from (1957-1960 and) 1963-1990.
Definitively, throwing a wobbly refers to Constable Plod, of Enid Blyton fame, whose cartoon character's head would wobble around anytime he became agitated or was confronted with a challenging situation. This is exactly the same meaning as today. It started out as a quaint idiosyncratic behaviour of a rather endearing cartoon character, and has matured into a standard description of anyone who's lost control and displaying erratic begaviour. I grew up in England in the 1950s, and Constable Plod "throwing a wobbly" was a source of delight to me as a young child as I watched Noddy and the rest of his friends.
CHUCK: Is the Aussie term for THROW WOBBLY: Is uncontrollable or or unstable shaking, as in a 'fit'.
Henceforth it follows that we Australians have 'converted' the English phrase to "throw a fit", into our own domestic terminology.
There's an interesting discussion here: http://www.wordwizard.com/phpbb3/viewtopic.php?f=7&t=20663
I find the most interesting suggestion here:
WOBBLY ►adjective (wobblier, wobbliest) unsteady; shaky; inclined to wobble. ►noun (wobblies) colloquial a fit of anger; a tantrum. • wobbliness noun. • throw a wobbly colloquial to have a tantrum; to rage. 1970s as a noun.
I always assumed "chuck a wobbly" was a reference to the propensity of the Industrial Workers of the World, aka Wobblies, to go on strike - which could be seen as a kind of tantrum-throwing, which is roughly what the modern phrase meant in the usage when I was growing up, long after the IWW had disappeared but not necessarily their cultural memory.
I would suggest it is derived from 'throwing a fit' and is intended as indicative of the involuntary spasms of someone suffering an epileptic seizure (commonly called 'a fit')
