No, it is not. Mountainous is an adjective meaning of, about, or like a mountain. The adverb form, mountainously, has very rare usage.
The noun mountain has the adjective form mountainous. The adverb form is "mountainously" (whether pertaining to an actual mountain, or metaphorically).
The terrain was mountainous.
it is mountains
Mountainous is an adjective.
Iceland is mountainous.
1. Adverb Of Time2. Adverb Of Place3. Adverb Of Manner4. Adverb Of Degree of Quantity5. Adverb Of Frequency6. Interrogative Adverb7. Relative Adverb
Yes, South Korea is mountainous.
Yes! Most of all Kosovo is mountainous !
Switzerland is noted for its mountainous terrain.
The root word of mountainous is "mountain."
Mountainous Croatia's population is 90,643.
"Ever" is an adverb.