Unlucky one left heaps to divide eats (7)
I believe the answer is:
hapless
'unlucky' is the definition.
(I've seen this in another clue)
'one left heaps to divide eats' is the wordplay.
'one left heaps' becomes 'ples' (I can't justify this - if you can you should give a lot more credence to this answer).
'to divide' is an insertion indicator (inserted letters divide the word).
'eats' becomes 'has' (I've seen this in another clue).
'ples' placed within 'has' is 'HAPLESS'.
Can you help me to learn more?
(Other definitions for hapless that I've seen before include "Unfortunate, wretched" , "Piteous" , "Ill-fated" , "Ill-starred" , "Pathetic" .)