When the suffix ous is added to word mountain it makes a new that means?

Adding the suffix "-ous" to "mountain" creates the word "mountainous".

Mountainous means:

* Relating to or resembling mountains

* Having many mountains

* Very large or high, like a mountain

For example:

* "The region is known for its mountainous terrain."

* "They hiked through a mountainous region."

* "The task was a mountainous undertaking."