Prestigious award presented by no-mark? (5)
I believe the answer is:
oscar
'prestigious award' is the definition.
(I've seen this in another clue)
'by no-mark?' is the wordplay.
'by' is a charade indicator (letters next to each other).
'no' becomes 'O' (resembles 0 - 'no' can mean 'zero').
'mark?' becomes 'scar' (mark left by an injury).
'o'+'scar' is 'OSCAR'.
'presented' is the link.
(Other definitions for oscar that I've seen before include "Cinema award" , "Phonetic code for O" , "Note" , "Film prize" , "US film award" .)