Terribly dim, indicates centres (9)

I believe the answer is:

midpoints

'centres' is the definition.
('midpoint' can be a synonym of 'centre')

'terribly dim indicates' is the wordplay.
'terribly' indicates an anagram.
'indicates' becomes 'points' ('point' can be a synonym of 'indicate').
'dim' anagrammed gives 'mid'.
'mid'+'points'='MIDPOINTS'

I've seen this clue in The Daily Express.

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