Island, unduly round land (6)
I believe the answer is:
tobago
'island' is the definition.
(Tobago is an example)
'unduly round land' is the wordplay.
'unduly' becomes 'too' (I've seen this before).
'round' indicates putting letters inside.
'land' becomes 'bag' (I've seen this in other clues).
'too' placed around 'bag' is 'TOBAGO'.
(Other definitions for tobago that I've seen before include "island location" , "Caribbean island" , "Section of WI" , "Island near Trinidad" , "Trinidad companion island" .)