What Does Mountainous Mean?

The word "mountainous" is an adjective meaning having numerous mountains or something that in its size resembles mountains. It can be associated to the noun mountain. The word mountain ciomes from the Middle English word "mountaine" which was taken from the Old French "montaigne" from the Vulgar Latin "montanea" derived from the Latin "montanus" meaning mountain. The word mountainous is synonymous with craggy, hilly and cragged.   

When something is being defined as being mountainous it means it is colossal, behemoth, heroic, immense, massive, huge, mighty, titanic etc in size, scope etc. The word can either define the geography of a place or the characteristics of something. For example "Afghanistan is a mountainous country" or "the waves hitting the beach were mountainous" etc.

Mountainous  means an area covered in mountains or large hills, it's that simple!