Crossword Genius

Slave man, one found in auction (5)

Ross

I believe the answer is:

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'slave' is the definition.
(slave in ancient Sparta)

'man one found in auction' is the wordplay.
'man' becomes 'he'.
'one found in auction' becomes 'lot' (I can't justify this - if you can you should give a lot more credence to this answer).
'he'+'lot'='HELOT'

Can you help me to learn more?

(Other definitions for helot that I've seen before include "He's bound to land", "Hotel (anag) - serf", "Greek serf", "Spartan serf", "Serf of ancient Sparta".)

I've seen this clue in The Guardian.