Sleazy sort endlessly cheated (6)
I believe the answer is:
sordid
'sleazy' is the definition.
(I know that sleazy can be written as sordid)
'sort endlessly cheated' is the wordplay.
'endlessly' means to remove the last letter.
'cheated' becomes 'did' (do can mean to cheat or trick).
'sort' with its final letter removed is 'sor'.
'sor'+'did'='SORDID'
(Other definitions for sordid that I've seen before include "Dirty, mean" , "Squalid, revolting" , "Mean and grubby" , "'Sleazy, squalid (6)'" , "Squalid, not honourable" .)