The girl adopted by father is frustrated (6)
I believe the answer is:
dashed
'is frustrated' is the definition.
(I've seen this before)
'the girl adopted by father' is the wordplay.
'the girl' becomes 'she'.
'adopted by' means one lot of letters goes inside another (I've seen this in other clues).
'father' becomes 'dad' (dad is a kind of father).
'she' placed inside 'dad' is 'DASHED'.
(Other definitions for dashed that I've seen before include "Flaming" , "hurled at" , "Darted headlong" , "completely spoiled" , "Moved very quickly or hastily" .)