By any means necessary (7)
'by any means necessary' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for one way or another that I've seen before include "Decision to be taken at a crossroads" , "somehow?" .)
(Other definitions for somehow that I've seen before include "By unspecified means" , "In a way not yet specified" , "For some unspecified reason" , "One way or another" , "By hook or by crook" .)