Disturb (8)

I think it could be either:

Which length description are you looking for?:

unsettle

'disturb' is the definition.
(I've seen this before)

This is all the clue.

(Other definitions for unsettle that I've seen before include "Disturb, make anxious" , "'Disturb, unnerve (8)'" , "Make someone ill at ease" , "Disrupt" , "Fluster" .)

I've seen this clue in The Guardian and the Evening Standard.

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