semi-mountainous

adjective

1. abounding in mountains: a mountainous wilderness.
2. of the nature of a mountain.
3. resembling a mountain or mountains, as being very large and high: mountainous waves.

adjective

1. of or relating to mountainsa mountainous region
2. like a mountain, esp in size or impressiveness

adj.late 14c., from Old French montagneux, from Vulgar Latin *montaneosus “mountainous,” from *montanea (see mountain).