IPA: /ˈtɪərər/
KK: /ˈtɪrər/
A person or thing that tears something apart or causes it to be torn.
The tearer of the paper left a mess on the floor.
Tearer → It is formed from "tear" (from Old English *teran*, meaning to pull apart or rip) and "-er" (meaning a person who). A tearer is a person who tears something apart.
Think of someone who 'pulls apart' ('tear') something — the '-er' just means a person. A tearer is someone who tears.