A Native American possessing a good area of land (7)
I believe the answer is:
acreage
'area of land' is the definition.
(I've seen this before)
'a native american possessing a good' is the wordplay.
'native american' becomes 'cree' (an indigenous people of North America).
'possessing' indicates putting letters inside.
'good' becomes 'g' (abbreviation).
'a'+'g'='ag'
'cree' placed around 'ag' is 'creage'.
'a'+'creage'='ACREAGE'
(Other definitions for acreage that I've seen before include "Measure of land" , "plot" , "good quantity of land" , "expanse" , "Amount of land" .)