Older sibling who keeps an unwelcome eye on you? (3,7)

I believe the answer is:

big brother

'who keeps an unwelcome eye on you?' is the definition.
(Big Brother is watching you)

'older sibling' is the wordplay.
'older' becomes 'big' (synonyms).
'sibling' becomes 'brother' (I've seen this before).
'big'+'brother'='BIG BROTHER'

(Other definitions for big brother that I've seen before include "dictatorial controller" , "Personification of a totalitarian state" , "TV programme" , "One keeping watch" , "oppressor, for Winston" .)

I've seen this clue in The Guardian.

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