Something of a cowboy song lieutenant's adopted (6)
I believe the answer is:
lariat
'something of a cowboy' is the definition.
I can't judge whether this definition defines the answer.
'song lieutenant's adopted' is the wordplay.
I cannot really see how this works, but
'song' could be 'aria' (piece of music in an opera) and 'aria' is present in the answer.
'lieutenant' could be 'lt' (abbreviation for lieutenant) and 'lt' is found within the leftover letters.
This accounts for all the letters.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for lariat that I've seen before include "Long narrow ditch" , "Long noosed rope for catching animals" , "Long noosed rope used to catch animals" , "tethering-rope" , "Line of cowboy" .)