Arrive rapidly around stream (5)
I believe the answer is:
river
'stream' is the definition.
(I know that river is a type of stream)
'arrive rapidly around' is the wordplay.
'around' indicates a hidden word.
'RIVER' is hidden within 'arrive rapidly'.
(Other definitions for river that I've seen before include "Type of watercourse" , "It flows" , "Eg, Amazon" , "course of 1d [ADVENTURE]" , "flower" .)