Timeless copies young lady's almost wearing (7)
I believe the answer is:
classic
'timeless' is the definition.
(thesaurus)
'copies young lady's almost wearing' is the wordplay.
I cannot quite understand how this works, but
'young lady's' could be 'lass' (lass is a kind of young lady) and 'lass' is found within the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for classic that I've seen before include "Traditional" , "of enduring significance" , "Artistic work of the highest excellence" , "Epsom Derby or St Leger Stakes, for example" , "Descriptive of ancient Rome and Greece" .)