Oxen tire out due to this? (8)

I believe the answer is:

exertion

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'this?' is the definition.
The definition suggests a singular noun which matches the answer.

'oxen tire out' is the wordplay.
'out' indicates anagramming the letters (out can mean wrong or inaccurate).
'oxen'+'tire'='oxentire'
'oxentire' is an anagram of 'EXERTION'.

'due to' acts as a link.

Can you help me to learn more?

(Other definitions for exertion that I've seen before include "Strenuous activity" , "Strain" , "labour" , "Physical/mental effort" , "Tire oxen with heavy effort" .)

I've seen this clue in The Sun.

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