Not against moving, but lack of movement (10)
I believe the answer is:
stagnation
'lack of movement' is the definition.
'stagnation' can be an answer for 'lack' (I have seen 'Lack of activity ' mean 'stagnation' so perhaps 'lack' could also mean 'stagnation'). I am not sure about the 'of movement' bit.
'not against moving' is the wordplay.
'moving' indicates an anagram (letters are moved around).
'not'+'against'='notagainst'
'notagainst' anagrammed gives 'STAGNATION'.
'but' is the link.
Can you help me to learn more?
(Other definitions for stagnation that I've seen before include "Process of reducing activity" , "It's still" , "Failure to develop" , "State of lethargy" , "Lack of movement or growth" .)