What it means
A wobbler is a full-on tantrum or emotional blow-up, usually over something petty. You’ll mostly hear it in the phrase throw a wobbler, meaning someone’s lost the plot and started kicking off. Works for toddlers in the pram or grown-ups in the queue. It’s not a serious breakdown, more a dramatic strop that makes everyone nearby cringe.
Usage examples
"He threw a right wobbler at the self-checkout when it ate his tenner, kicking off loud enough for the whole Tesco to clock it."
"He threw a right wobbler when the cafe ran out of his usual sandwich, stormed off and everything."
"The toddler chucked a wobbler in the supermarket because I wouldn't buy the dinosaur cereal."
"She threw a proper wobbler when they said breakfast had finished, like the whole café had personally betrayed her."
"Don’t chuck a wobbler, mate, it’s only a ten-minute delay and nobody’s nicked your seat."
Where it comes from
This is solid British slang. It comes from the older phrase throw a wobbly, where wobbly meant shaky or unsteady. By the late 20th century, that wobble got turned into a comic tantrum sense, and wobbler followed as the fit itself or the person kicking off in that overdramatic way.