The person disembarking from the boat (7)
I believe the answer is:
lighter
'boat' is the definition.
(lighter is a kind of boat)
'the person disembarking' is the wordplay.
I cannot really see how this works, but
an anagram of 'the' is 'hte' which is present in the answer.
This may be the basis of the clue (or it may be nonsense).
'from the' is the link.
Can you help me to learn more?
(Other definitions for lighter that I've seen before include "- boot; - bun; - ware" , "Flat-bottomed boat" , "Barge; flame producer" , "Tender, launch" , "Less weighty" .)