Person who's moved abroad rating me badly (8)
I believe the answer is:
emigrant
'person' is the definition.
(emigrant is a kind of person)
'rating me badly' is the wordplay.
'badly' indicates anagramming the letters (letters in the wrong order).
'rating'+'me'='ratingme'
'ratingme' anagrammed gives 'EMIGRANT'.
'who's moved abroad' acts as a link.
This may not be right. Some or all of it may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for emigrant that I've seen before include "One settling abroad" , "Time Gran went abroad to settle" , "One leaving for another country" , "One who leaves to live in another country" , "One going abroad permanently" .)