Disreputable character mostly cheated (6)
I believe the answer is:
sordid
'disreputable' is the definition.
(similar in meaning)
'character mostly cheated' is the wordplay.
'character' becomes 'sord' (I am not sure about this - if you are sure you should believe this answer much more).
'mostly' means to remove the first letter.
'cheated' becomes 'did'.
'did' with its first letter taken away is 'id'.
'sord'+'id'='SORDID'
Can you help me to learn more?
(Other definitions for sordid that I've seen before include "Unclean" , "Squalid - base" , "Filthy - base" , "Squalid and disgusting" , "Squalid, revolting" .)