Dishonourable man runs away from Jack, perhaps (3)
I believe the answer is:
cad
'dishonourable man' is the definition.
(cad can mean a dishonourable person)
'runs away from jack perhaps' is the wordplay.
'runs' becomes 'r' (cricket abbreviation).
'away from' indicates named letters should be taken away.
'jack perhaps' becomes 'card' (jack is a playing card).
'card' with 'r' taken out is 'CAD'.
(Other definitions for cad that I've seen before include "Heel" , "Blackguard" , "An Englishman who behaves dishonourably, a rotter" , "Wretch" , "Rogue" .)