Everything that helotism contains (3,3)
I believe the answer is:
the lot
'everything' is the definition.
('the lot' means everything from a selection)
'that helotism contains' is the wordplay.
'contains' indicates the answer is hidden within the clue.
'THE LOT' is hidden in the letters of 'that helotism'.
(Other definitions for the lot that I've seen before include "Everything" , "goes under the hammer" .)