Partly explode prototype spinning missile (7)
I believe the answer is:
torpedo
'missile' is the definition.
(thesaurus)
'partly explode prototype spinning' is the wordplay.
'partly' indicates the answer is hidden within the clue.
'spinning' says the letters should be written in reverse.
'odeprot' is hidden within 'explode prototype'.
'odeprot' in reverse letter order is 'TORPEDO'.
(Other definitions for torpedo that I've seen before include "Self-propelled underwater explosive device" , "electric ray" , "Explosive missile from submarine" , "Weapon travelling under water" , "Anti-ship weapon" .)