Criminal: villain online nailing two consecutive characters (8)
I believe the answer is:
hijacker
'criminal' is the definition.
(hijacker is a kind of criminal)
I can't explain the remainder of the clue.
Can you help me to learn more?
(Other definitions for hijacker that I've seen before include "One forces a pilot to fly to a chosen destination" , "One seizing control of plane" , "Plane or ship seizer" , "One who steals en route" , "Seizer of vehicle controls" .)