A flirt with no worries (2,4)

I believe the answer is:

at ease

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'with no worries' is the definition.
(I've seen this before)

'a flirt' is the wordplay.
'flirt' becomes 'tease' (I can't justify this - if you can you should give a lot more credence to this answer).
'a'+'tease'='AT EASE'

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(Other definitions for at ease that I've seen before include "Free from anxiety" , "Military order to relax from attention" , "In a relaxed attitude" , "Calm" , "Army command to relax, stand with feet apart" .)

I've seen this clue in The Telegraph.

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