Refuse to acknowledge adopting position out of such stupidity? (7)
I believe the answer is:
density
'stupidity?' is the definition.
(thesaurus)
'refuse to acknowledge adopting position' is the wordplay.
'refuse to acknowledge' becomes 'deny' (I've seen this before).
'adopting' is an insertion indicator.
'position' becomes 'sit' (sitting is a kind of positioning).
'deny' placed around 'sit' is 'DENSITY'.
'out of such' acts as a link.
(Other definitions for density that I've seen before include "The compactness of a substance" , "Mass/unit vol. (phys.)" , "showing obtuseness" , "Closeness" , "Concentrated condition as of fog" .)