On the street I run activity (4)
I believe the answer is:
Here is my best explanation:
'activity' is the definition.
'on the street i run' is the subsidiary indication.
'on' is a charade indicator (letters next to each other).
'the street' becomes 'st'.
'run' becomes 'r' (cricket abbreviation).
'st'+'i' is 'sti'.
(Other definitions for stir that I've seen before include "unrest", "Commotion; agitate", "Start to move", "Thrill", "Move around and mix thoroughly", "Stimulate; prison", "Commotion - prison", "Wake up - prison", "Cooler" and "Move around in a liquid".)