IPA: /ˈklætərɪŋli/
KK: /ˈklætərɪŋli/
In a way that makes a loud, rattling noise, often associated with objects hitting each other.
The dishes fell clatteringly to the floor, creating a loud noise.
Clatteringly is formed from "clatter" (from Middle English *clatren*, meaning to make a loud noise) and the suffix "-ingly" (meaning in a manner of). The word describes an action done in a noisy or clattering manner.
Think of the loud noise made when things collide or fall — that's what 'clatter' means, and the '-ingly' shows how it's done, making it clatteringly noisy.