Girl in Kashmir isolating (4)
I believe the answer is:
iris
'girl' is the definition.
'in kashmir isolating' is the wordplay.
'in' indicates a hidden word.
'IRIS' is hidden in the letters of 'kashmir isolating'.
(Other definitions for iris that I've seen before include "Eye diaphragm" , "Coloured part of the lamp" , "Flower - rainbow" , "Rainbow-goddess" , "Lily" .)