It's often used to form adjectives, but can sometimes be used to form nouns.
Here are some examples:
* Dangerous: Full of danger
* Fabulous: Characterized by being amazing or wonderful
* Courageous: Having the quality of courage
* Curious: Full of curiosity
* Victorious: Having the quality of being victorious
The suffix "-ous" often, but not always, comes after a root word ending in a consonant.