America’s ready to embrace new Society, being stupid (7)
I believe the answer is:
dimness
'being stupid' is the definition.
(being stupid or dim)
'america's ready to embrace new society' is the wordplay.
'america's ready' becomes 'dimes' (US coins - 'ready' can mean cash).
'to embrace' means one lot of letters goes inside another.
'new' becomes 'n' (common abbreviation eg NT for New Testament).
'society' becomes 's' (common abbreviation in names of organisations).
'dimes' going around 'n' is 'dimnes'.
'dimnes'+'s'='DIMNESS'
(Other definitions for dimness that I've seen before include "Dark" , "exhibiting stupidity" , "That's not very clever" , "Quality of dull light" , "Shortage of light; weakness of intellect" .)