Healthy colour in Istanbul (3)
I believe the answer is:
tan
'healthy colour' is the definition.
'in istanbul' is the wordplay.
'in' says the answer is hidden in the clue.
'TAN' is hidden in the letters of 'istanbul'.
(Other definitions for tan that I've seen before include "Brown colour acquired from sun" , "Yellowish-brown colour" , "function" , "Make black and blue" , "Acquire a sunburn" .)