Lack of progress from unruly antagonist (10)
I believe the answer is:
stagnation
'lack of progress' is the definition.
(I've seen this in another clue)
'unruly antagonist' is the wordplay.
'unruly' indicates anagramming the letters.
'antagonist' with letters rearranged gives 'STAGNATION'.
'from' acts as a link.
(Other definitions for stagnation that I've seen before include "movement's antithesis?" , "Lack of activity" , "Lack of movement or growth" , "sluggish" , "making no progress" .)