Listen stupid recruit! (6)
I believe the answer is:
enlist
'recruit' is the definition.
(I know this)
'listen stupid' is the wordplay.
'stupid' indicates anagramming the letters (in a stupid order).
'listen' is an anagram of 'ENLIST'.
(Other definitions for enlist that I've seen before include "Obtain help of" , "Enrol - recruit" , "Enrol in armed forces" , "Listen (anag.)" , "Engage" .)