Sailor's container wrapped in poor paper (6)
I believe the answer is:
rating
'sailor's' is the definition.
(British term for a naval enlisted man)
'container wrapped in poor paper' is the wordplay.
'container' becomes 'tin' (tin is a kind of container).
'wrapped in' means one lot of letters goes inside another.
'poor paper' becomes 'rag' (rag can mean a newspaper. I am not sure about the 'poor' bit.).
'tin' put into 'rag' is 'RATING'.
Can you help me to learn more?
(Other definitions for rating that I've seen before include "Sailor - deserving - reprimand" , "Score" , "Grading; sailor" , "level" , "Sailor - assessment" .)