Distinguish inverted section in Opel bonnet (7)
I believe the answer is:
ennoble
'distinguish' is the definition.
(I've seen this before)
'inverted section in opel bonnet' is the wordplay.
'inverted' says the letters should be written backwards.
'section' indicates a hidden word.
'elbonne' is hidden in the letters of 'in opel bonnet'.
'elbonne' written backwards gives 'ENNOBLE'.
(Other definitions for ennoble that I've seen before include "Raise to the knighthood or make more dignified" , "Raise status" , "Lend dignity or honour to" , "Elevate with a title" , "Make a count, perhaps" .)