Essentially impertinent comment about commercial logo (9)
I believe the answer is:
trademark
'logo' is the definition.
(thesaurus)
'essentially impertinent comment about commercial' is the wordplay.
'essentially' says to take the centre.
'comment' becomes 're-mark' (a remark is a spoken comment).
'about' is an insertion indicator.
'commercial' becomes 'ad' (abbreviation for advertisement).
The centre of 'impertinent' is 't'.
'remark' placed around 'ad' is 'rademark'.
't'+'rademark'='TRADEMARK'
(Other definitions for trademark that I've seen before include "sign of concern" , "Proprietary name" , "Registered company symbol" , "Brand - identifying symbol" , "Distinctive sign" .)