Is able to steal one's pot? (8)
I believe the answer is:
cannabis
'pot?' is the definition.
('cannabis' can be a synonym of 'pot')
'is able to steal one's' is the wordplay.
'is able to' becomes 'can' (if you can do something you are able to do it).
'steal' becomes 'nab' (I can't explain this - if you can you should give a lot more credence to this answer).
'one's' becomes 'I's' (Roman numeral).
'can'+'nab'+'is'='CANNABIS'
Can you help me to learn more?
(Other definitions for cannabis that I've seen before include "Hemp plant for making intoxicant drug" , "Smoked drug" , "Marijuana" , "Most commonly used (mostly) illicit drug" , "illegal drug supply" .)