Generate, with "up" (4)
I believe the answer is:
drum
'generate with up' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for drum that I've seen before include "one will be beaten" , "Empty" , "(Revolving) cylinder" , "Iris rootstock (perfume)" , "Thing to be beaten - but not as a container!" .)