incredible, incredulous Definition

incredible
adj

1. Difficult or impossible to believe; unbelievable.

Thesaurus: unbelievable, implausible, unlikely, improbable, ridiculous, preposterous.
2. colloq
Amazing; unusually good.

Derivative: incredibility
noun

Derivative: incredibly

In an incredible way, or so as to be incredible.

colloq
Extremely.
Example: I'm incredibly grateful

Etymology: 15c.

Info:

These words are often confused with each other.