IPA: /ˈlɪtərər/
KK: /ˈlɪtərər/
A person who throws waste or trash in public places instead of putting it in a bin.
The park was clean until a litterer left their garbage on the ground.
Litterer → It is formed from "litter" (from Old French *litiere*, meaning bed or bedding) and "-er" (meaning a person who). A litterer is a person who leaves waste or litter, as if they are treating the ground like a bed for trash.
Think of someone who treats the ground like a 'bed' ('litter') by leaving trash behind — that's why a litterer is someone who litters.