Stupid action she condemned as naive (15)
I believe the answer is:
unsophisticated
'naive' is the definition.
(similar in meaning)
'stupid action she condemned' is the wordplay.
'condemned' indicates an anagram.
'stupid'+'action'+'she'='stupidactionshe'
'stupidactionshe' with letters rearranged gives 'UNSOPHISTICATED'.
'as' acts as a link.
(Other definitions for unsophisticated that I've seen before include "Lacking experience" , "Simple" , "green" , "straightforward" , "crude" .)