Gun used by governor in uprising (3)
I believe the answer is:
rev
'gun' is the definition.
(as in gunning or revving up a car engine)
'by governor in uprising' is the wordplay.
'in' indicates a hidden word.
'uprising' shows that the letters should be reversed in order.
'ver' is hidden within 'by governor'.
'ver' reversed gives 'REV'.
'used' acts as a link.
(Other definitions for rev that I've seen before include "Clergyman, or woman (abbr)" , "Motor rotation, in short" , "In engine-room speed up" , "Cleric" , "Accelerate (abbrev.)" .)