Gold 1000kg ring? Gosh, that's freedom (8)
I believe the answer is:
autonomy
'that's freedom' is the definition.
(autonomy is a kind of freedom)
'gold 1000kg ring? gosh' is the wordplay.
'gold' becomes 'Au' (Au is the chemical symbol for gold).
't000kg' becomes 'ton' (I can't justify this - if you can you should give a lot more credence to this answer).
'ring?' becomes 'o' (O is the shape of a ring).
'gosh' becomes 'my' (both are old-fashioned expressions of surprise).
'au'+'ton'+'o'+'my'='AUTONOMY'
Can you help me to learn more?
(Other definitions for autonomy that I've seen before include "Self-rule" , "'Independence, self-sufficiency (8)'" , "Independence or self-government, even unto Mayo" , "Independence, freedom to govern" , "The right or condition of self-government" .)