Real wrongdoing by church upset Her Majesty (7)
I believe the answer is:
sincere
'real' is the definition.
('sincere' can be similar in meaning to 'real')
'wrongdoing by church upset her majesty' is the wordplay.
'wrongdoing' becomes 'sin' (sin is a kind of wrongdoing**).
'by' says to put letters next to each other.
'church' becomes 'ce' (abbreviation for Church of England).
'upset' is a reversal indicator.
'her majesty' becomes 'er' (Elizabeth Regina).
'er' written backwards gives 're'.
'sin'+'ce'+'re'='SINCERE'
(Other definitions for sincere that I've seen before include "(Of person) genuine" , "Free from deceit" , "Unaffected" , "Not hypocritical" , "Pure" .)