Rogue's name for a former army corps (6)
I believe the answer is:
rascal
'rogue's' is the definition.
(synonyms)
'name for a former army corps' is the wordplay.
'name' becomes 'Cal'.
'for' is a charade indicator (letters next to each other) (I've seen this in other clues).
'a former army corps' becomes 'ras' (I can't explain this - if you can you should believe this answer much more).
'cal' put after 'ras' is 'RASCAL'.
Can you help me to learn more?
(Other definitions for rascal that I've seen before include "Lascar (anag.)" , "Mischievous or cheeky child" , "Rogue of a lascar" , "A mischievous and maybe dishonest person" , "Impudent person" .)