Guiltless wife finally accepted by family group (5)
I believe the answer is:
clean
'guiltless' is the definition.
(I've seen this in another clue)
'wife finally accepted by family group' is the wordplay.
'finally' says to take the final letters.
'accepted by' is an insertion indicator (inserted letters are accepted).
'family group' becomes 'clan' (I've seen this before).
The last letter of 'wife' is 'e'.
'e' going into 'clan' is 'CLEAN'.
(Other definitions for clean that I've seen before include "Quite" , "Completely (colloq.), free of dirt" , "Pure; well-defined" , "Untarnished" , "Second part of 18" .)