Pretty remote island is splitting (4)
I believe the answer is:
fair
'pretty' is the definition.
(both can mean beautiful or attractive)
'remote island is splitting' is the wordplay.
'remote' becomes 'far' (similar in meaning).
'island' becomes 'i' (geographical abbreviation).
'is splitting' indicates putting letters inside (some letters split a word into two).
'far' enclosing 'i' is 'FAIR'.
(Other definitions for fair that I've seen before include "not cloudy" , "Impartial, so-so" , "likely" , "Just; beautiful; blond" , "All clues should be" .)