If angle thirteen breaks it will be hazardous (4-11)

I believe the answer is:

life-threatening

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'if angle thirteen breaks it will be hazardous' is the definition.
I can't tell whether this defines the answer.

'if angle thirteen breaks' is the wordplay.
'breaks' indicates an anagram.
'if'+'angle'+'thirteen'='ifanglethirteen'
'ifanglethirteen' anagrammed gives 'LIFE-THREATENING'.

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I've seen this clue in the Sydney Morning Herald.

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