Approve the head's portrait (8)
I believe the answer is:
likeness
'portrait' is the definition.
(I've seen this before)
'approve the head's' is the wordplay.
'approve' becomes 'like' (I've seen this before).
'the head' becomes 'ness' (ness is a headland).
'like'+'ness'='LIKENESS'
(Other definitions for likeness that I've seen before include "Similarity - faithful portrait" , "Image - comparison" , "impression" , "depiction" , "Similarity in appearance" .)