Lubberly ways, to a seaman (4)
I believe the answer is:
swab
'lubberly ways' is the definition.
The definition and answer can be both man-made objects as well as being singular nouns.
Maybe there's an association between them I don't understand?
'to a seaman' is the wordplay.
'to a' becomes 'sw' (I can't justify this - if you can you should give a lot more credence to this answer).
'seaman' becomes 'ab' (short for able seaman).
'sw'+'ab'='SWAB'
Can you help me to learn more?
(Other definitions for swab that I've seen before include "Small piece of cotton used to cleanse a wound" , "Among others, Q-tip" , "Absorbent pad for cleansing or drying" , "Cloth for cleaning wounds" , "Wound-cleaner" .)