Potentially moving article thus containing inferior material (7)
I believe the answer is:
astatic
'potentially moving' is the definition.
(astatic is the opposite of static)
'article thus containing inferior material' is the wordplay.
'article' becomes 'a' (the indefinite article in English).
'thus' becomes 'sic' ('thus' in Latin).
'containing' is an insertion indicator.
'inferior material' becomes 'tat' (tat can mean low-quality items).
'sic' enclosing 'tat' is 'static'.
'a'+'static'='ASTATIC'
(Other definitions for astatic that I've seen before include "unable to stay still?" , "move about" , "without determination or polarity" .)