Genuine, almost as before (7)
I believe the answer is:
sincere
'genuine' is the definition.
(sincere can mean authentic or genuine)
'almost as before' is the wordplay.
'almost' means to remove the last letter (most of the word but not all of it).
'as' becomes 'since' (both can mean 'because').
'before' becomes 'ere' (poetic term for 'before').
'since' with its last letter taken away is 'sinc'.
'sinc'+'ere'='SINCERE'
(Other definitions for sincere that I've seen before include "Not hypocritical" , "Unfeigned, genuine" , "like informal correspondents?" , "Earnest" , "Genuine and honest" .)