IPA: /ˈstɪrər/
KK: /ˈstɪrər/
A tool or device used to mix substances, especially liquids, or a person who causes excitement or trouble.
She used a wooden stirrer to mix the paint thoroughly.
Stirrer → It is formed from "stir" (from Old English *styrrian*, meaning to move or agitate) and "-er" (meaning a person who). A stirrer is a person or tool that moves or agitates something, typically a liquid.
Think of someone who 'moves' ('stir') something around — that's why a stirrer is a person or tool that stirs.