Old lady's man on board in Chinese port (7)
I believe the answer is:
nanking
'board in chinese port' is the definition.
'nanking' can be an answer for 'port' (I've seen this before). I'm unsure of the 'board in chinese' bit.
'old lady's man on' is the wordplay.
'old lady' becomes 'nan' (British slang for grandmother).
'man' becomes 'king' (man can mean a chess piece).
'on' is a charade indicator (letters next to each other).
'nan'+'king'='NANKING'
Can you help me to learn more?
(Other definitions for nanking that I've seen before include "Chinese city" , "Eastern city" , "Oriental city" , "Port" .)