Take off topless summer wear (7)

I believe the answer is:

undress

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'take' is the definition.
(I know that undress is a type of take)

'off topless summer wear' is the wordplay.
'off topless summer' becomes 'un' (I am not sure about this - if you are sure you should believe this answer much more).
'wear' becomes 'dress' (both can mean a person's clothing).
'un'+'dress'='UNDRESS'

Can you help me to learn more?

(Other definitions for undress that I've seen before include "Disrobe - uniform for ordinary occasions" , "Divest of clothes" , "Nudity" , "Take off clothing, strip" , "Strip, take off clothes" .)

I've seen this clue in The Guardian.

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