Delay can be criminal! (4-2)
I believe the answer is:
hold-up
'delay' is the definition.
(I know that delay can be written as hold up)
'be criminal' is the wordplay.
'be' becomes 'hold' (holding is a kind of being).
'criminal' becomes 'up' (I am not sure about this - if you are sure you should believe this answer much more).
'hold'+'up'='HOLD-UP'
'can' acts as a link.
Can you help me to learn more?
(Other definitions for hold-up that I've seen before include "Robbery with violence" , "Commit armed robbery or keep aloft" , "Situation causing delay" , "Delay or show aloft" , "A delay, or an armed robbery" .)