One taking stock of another (7)
I believe the answer is:
rustler
'one taking stock' is the definition.
(someone stealing farm animals ie stock)
I don't understand the rest of the clue.
Can you help me to learn more?
(Other definitions for rustler that I've seen before include "Stock taker?" , "Cattle-thief" , "one whose stock-taking is dishonest" , "Stealer of livestock" , "Cattle stealer" .)