Wrong: Charlie before Frank (7)
I believe the answer is:
sincere
'frank' is the definition.
(similar in meaning)
'wrong charlie before' is the wordplay.
'wrong' becomes 'sin' (I've seen this before).
'charlie' becomes 'c' (phonetic alphabet: alpha, bravo, charlie etc.).
'before' becomes 'ere' (poetic term for 'before').
'sin'+'c'+'ere'='SINCERE'
(Other definitions for sincere that I've seen before include "devout" , "Unaffected" , "Free from deception" , "Honest, heartfelt" , "Earnest" .)