Opaque
Opaque explained in an easy to understand way:
Imagine trying to have a conversation with a friend over the phone, but there's no signal, and your words don't reach them at all. This situation is similar to how opaque materials behave with light—they completely block any light from passing through, just as the lack of a signal prevents your voice from getting through. In both cases, whether it’s your voice or light, the intended message or beam is stopped entirely, leaving no way for it to continue to the other side.
Practice Version
Opaque: A material that does not let any light pass through. Opaque. An opaque object blocks light completely, so you can't see through it at all.