Sneaky behaviour from clever jerk engaged in dodgy caper (5,8)
I believe the answer is:
sharp practice
'sneaky behaviour' is the definition.
(sharp practice means dishonest behaviour)
'clever jerk engaged in dodgy caper' is the wordplay.
'clever' becomes 'sharp'.
'jerk' becomes 'tic' (I've seen this before).
'engaged in' means one lot of letters goes inside another.
'dodgy caper' becomes 'prace' (I can't explain this - if you can you should believe this answer much more).
'tic' inserted inside 'prace' is 'practice'.
'sharp'+'practice'='SHARP PRACTICE'
'from' is the link.
Can you help me to learn more?
(Other definitions for sharp practice that I've seen before include "cheating" , "fiddle" , "Dishonesty" , "Dodgy dealings" , "Ethically dubious machination" .)