stir somebody/something ↔ up phrasal verb ( see also ↑ stir )
1 . to deliberately try to cause arguments or bad feelings between people:
John was always stirring up trouble in class.
Dave’s just trying to stir things up because he’s jealous.
2 . to make small pieces of something move around in the air or in water:
The wind had stirred up a powdery red dust.