One who steals, but not silently (7)
I believe the answer is:
rustler
'one who steals but not silently' is the definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.
This is the entire clue.
Can you help me to learn more?
(Other definitions for rustler that I've seen before include "Horse thief" , "Stealer of livestock" , "person taking stock" , "lawbreaker" , "Cattle-thief" .)