Mountainous \Moun"tain*ous\, a. [F. montagneux, L. montaniosus.]

1. Full of, or containing, mountains; as, the mountainous country of the Swiss.

2. Inhabiting mountains. [Obs.]

--Bacon.

3. Large as, or resembling, a mountain; huge; of great bulk; as, a mountainous heap. --Prior.

Source: Webster's Revised Unabridged Dictionary (1913)