stir = حرك = haraka:
When we're talking about things in liquid state like tea, coffee, milk, ...etc
Ex. حرك كاسة الشاي = haraka kasata-lshaai = stir the tea cup
(After adding sugar to the cup)
stir = خلط = khalata
When we are talking about things in solid state like when you add some broth to rice (very common) and then stir them
Ex. خلط الرز مع المرقة = khalata alruz ma'a-lmarqa = stir rice and broth