Man that can jump on board? (6)
I believe the answer is:
knight
'man that can jump on board?' is the definition.
'knight' can be an answer for 'man' (man can mean a piece in chess). I'm not sure about the rest of the definition.
'man that can jump on' is the wordplay.
'man' becomes 'k' (abbreviation for king, a chess man).
'that can jump on' becomes 'night' (I am not sure about this - if you are sure you should believe this answer much more).
'k'+'night'='KNIGHT'
Can you help me to learn more?
(Other definitions for knight that I've seen before include "Old horseman (on board?)" , "... for example, Tippett" , "Chess piece shaped like hors's head" , "In Britain, a person honoured by the sovereign for personal merit" , "Honour" .)