Embarrassed as editor engages amateur (7)
I believe the answer is:
ashamed
'embarrassed' is the definition.
(similar in meaning)
'as editor engages amateur' is the wordplay.
'editor' becomes 'ed'.
'engages' means one lot of letters goes inside another.
'amateur' becomes 'ham'.
'as'+'ed'='ased'
'ased' placed around 'ham' is 'ASHAMED'.
(Other definitions for ashamed that I've seen before include "Troubled by feelings of guilt or embarrassment" , "Feeling embarrassed" , "Feeling guilty" , "Feeling remorse and contrition" , "Afflicted with remorse, feeling sense of wrongdoing" .)