IPA: /ˈdɪmli/
KK: /dɪmli/
In a way that is not bright or clear; with little light.
The room was dimly lit, creating a cozy atmosphere.
Dimly → It is formed from "dim" (from Old English *dimm*, meaning not bright or obscure) and "-ly" (a suffix used to form adverbs). The word "dimly" means in a manner that is not bright or is obscure.
Think of the word 'dim' meaning not bright, and remember that 'dimly' describes something that is not bright in a way.