Moves at speed in waterworks (5)
I believe the answer is:
tears
This could be a double definition.
'moves' is the first definition.
(tear is a kind of move)
'speed in waterworks' is the second definition.
'tears' can be an answer for 'waterworks' (I've seen this in another clue). I'm not sure about the 'speed in' bit.
'at' acts as a link.
Can you help me to learn more?
(Other definitions for tears that I've seen before include "drops and > drop special > rushes" , "Rips; droplets" , "Lacerations (before bedtime?)" , "Rents" , "Shed them in sadness" .)