Gent's clothing classic, being dressed down (4,3)
I believe the answer is:
told off
'dressed down' is the definition.
(telling off is a kind of dressing down)
'gent's clothing classic' is the wordplay.
'gent' becomes 'toff' (term for an upper-class person).
'clothing' indicates putting letters inside (some letters cover up or clothe others).
'classic' becomes 'old'.
'toff' going around 'old' is 'TOLD OFF'.
'being' acts as a link.
(Other definitions for told off that I've seen before include "Rebuked" , "carpeting?" .)