Young lady is in Marks & Spencer? (4)

I believe the answer is:

miss

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'young lady' is the definition.
(term of address for a young woman)

'is in marks spencer?' is the wordplay.
'in' is an insertion indicator.
'marks spencer?' becomes 'ms' (this might be a standard abbreviation of which I'm unaware).
'is' inserted inside 'ms' is 'MISS'.

Can you help me to learn more?

(Other definitions for miss that I've seen before include "Feel the absence of" , "maiden" , "Fail to meet - girl" , "Single girl" , "state" .)

I've seen this clue in The Sun.

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