Tried case of arsonist enticed to do wrong (9)
I believe the answer is:
attempted
'tried case of arsonist' is the definition.
'attempted' can be an answer for 'tried' ('attempt' can be a synonym of 'try'). I am not sure about the 'case of arsonist' bit.
'enticed to do wrong' is the wordplay.
'enticed' becomes 'tempted' ('tempt' can be a synonym of 'entice').
'to' says to put letters next to each other (I've seen this in other clues).
'do wrong' becomes 'at' (I can't explain this - if you can you should believe this answer much more).
'tempted' after 'at' is 'ATTEMPTED'.
Can you help me to learn more?
(Other definitions for attempted that I've seen before include "Made an effort to accomplish something" , "Tried" , "Endeavoured" .)