Some runner vexed, upset (7)

I believe the answer is:

unnerve

'upset' is the definition.
(to unnerve is to upset or disturb)

'some runner vexed' is the wordplay.
'some' indicates the answer is hidden within the clue (some of the parts of the word are used).
'UNNERVE' is hidden within 'runner vexed'.

(Other definitions for unnerve that I've seen before include "Disturb the composure of" , "Deprive of courage" , "Discourage - demoralise" , "spook" , "Cause to lose courage - even run away" .)

I've seen this clue in The Times.

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