Weaken a standard? (4)

I believe the answer is:

flag

I believe this is a double definition.

'weaken' is the first definition.
(I've seen this in another clue)

'a standard?' is the second definition.
(standard is a kind of flag)

(Other definitions for flag that I've seen before include "Rectangular piece of fabric used as a signalling device" , "Iris; pennant" , "fade" , "Iris - paving slab" , "National standard" .)

I've seen this clue in the Evening Standard.

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