Island, in part, a must-see from the east (7)
I believe the answer is:
sumatra
'island' is the definition.
(Sumatra is an example)
'in part a must-see from the east' is the wordplay.
'in' indicates the answer is hidden within the clue.
'see from the east' is a reversal indicator.
'artamus' is hidden in the letters of 'part a must'.
'artamus' in reverse letter order is 'SUMATRA'.
(Other definitions for sumatra that I've seen before include "Island in western Indonesia" , "Large island of Indonesia" , "Eastern island" , "part of Indonesia" , "island in Indian ocean" .)