Measurements taken by weightwatchers around morning (9)

I believe the answer is:

diameters

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'measurements' is the definition.
(diameter is a kind of measurement)

'weightwatchers around morning' is the wordplay.
'weightwatchers' becomes 'dieters' (I can't justify this - if you can you should believe this answer much more).
'around' indicates putting letters inside.
'morning' becomes 'am' (as in di:00 AM).
'dieters' enclosing 'am' is 'DIAMETERS'.

'taken by' is the link.

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I've seen this clue in The Irish Times.

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