How to address an expensive woman (4)

I believe the answer is:

dear

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'address an expensive woman' is the definition.
'dear' can be an answer for 'address' (I've seen this before). I'm not certain of the 'an expensive woman' bit.

I don't understand the remainder of the clue.

Can you help me to learn more?

(Other definitions for dear that I've seen before include "Overpriced" , "At a high cost" , "Beloved or costly" , "letter opener" , "Baby" .)

I've seen this clue in the Evening Standard.

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