an adjective is a part of speech used to describe or modify a noun, pronoun, or other adjective. It is used to create a clearer picture of an object or person being discussed in order to allow for a more precise description.
use cases of 'incredible' when used as an adjective include describing something like an experience, event, person, etc. as 'incredible' usually meaning extraordinary or something breathtaking.
I watched the most incredible sunset that I’ve ever seen.
My friend made an incredible speech on why we should keep the planet clean.
The wedding dress was so incredibly beautiful.
tips and nuances associated with its use include 'incredible' often being used as an adjective, but not usually to describe people.