Being hunted, one imagines, breaks ranks (5)
I believe the answer is:
snark
'being hunted one imagines' is the definition.
I don't know anything about this answer so I can't judge whether this works.
'breaks ranks' is the wordplay.
'breaks' indicates anagramming the letters.
'ranks' with letters rearranged gives 'SNARK'.
Can you help me to learn more?
(Other definitions for snark that I've seen before include "One hunted by sailors" , "Animal hunted in verse" , "One famously hunted" , "Hunt creature (Carroll)" , "The hunting of the - (Lewis Carroll)" .)