First rip off the army stupid (7)
I believe the answer is:
primary
'first' is the definition.
('primary' is associated in meaning with 'first')
'rip off the army stupid' is the wordplay.
'off' indicates anagramming the letters.
'stupid' indicates an anagram (in a stupid order).
'rip' anagrammed gives 'pri'.
'army' anagrammed gives 'mary'.
'pri'+'mary'='PRIMARY'
(Other definitions for primary that I've seen before include "Of the first order" , "Main" , "Principal" , "Of chief importance" , "Paramount" .)