The most common and most likely answer to this crossword clue is the 7 letter word TANTRUM
I've seen this crossword clue in The Times
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More clues leading to the result TANTRUM
- Worker, having drink after time, displays a fit of temper
- Flare-up brought about by so much French spirit?
- So much French spirit causes outburst
- Paddy, dry, swallowing an alcoholic drink
- Worker interrupting start of this odd outburst
- So much French booze leads to furious scene
- Tense worker’s strange pet
- Paddy‘s social worker received by the president? Not quite
- Fit French aunt didn’t finish drink
- Brown shirt, odd fit
Buddy explains!

The straight part
We know that "outburst" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case outburst = tantrum.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does TANTRUM mean?
TANTRUM noun- An often childish display or fit of bad temper.
- To throw a tantrum.