Two ways to make a grab using perhaps dubious means (2,4,2,2,5)
I believe the answer is:
by hook or by crook
'using perhaps dubious means' is the definition.
'two ways to make a grab' is the subsidiary indication.
I cannot really see how this works, but
'grab' could be 'hook' (hooking is a kind of grabbing) and 'hook' is present in the answer.
This explanation may well be incorrect...
(Other definitions for by hook or by crook that I've seen before include "using any means" , "Somehow" .)