Turned up representative device for moving fluids (4)
I believe the answer is:
pump
'device for moving fluids' is the definition.
(I've seen this before)
'turned up representative' is the wordplay.
'turned' says the letters should be written backwards.
'representative' becomes 'mp'.
'up' in reverse letter order is 'pu'.
'pu'+'mp'='PUMP'
(Other definitions for pump that I've seen before include "Raise liquid or air" , "Fire bullets rapidly" , "Fluid moving device" , "Compressing machine" , "Fluid mover" .)