mountainous

adjective

moun·​tain·​ous ˈmau̇n-tə-nəs 

ˈmau̇nt-nəs

1

: containing many mountains

mountainous wilderness

2

: resembling a mountain : huge

a stormy ocean with mountainous waves

mountainously adverb

mountainousness noun

Synonyms of mountainous

• vast
• huge
• gigantic
• enormous
• giant
• massive
• tremendous
• colossal
• mammoth
• immense
• astronomical
• monumental
• monstrous

Examples of mountainous in a Sentence

the seemingly mountainous obstacles he had to overcome while growing up

Recent Examples on the Web

Selva de Irati in Navarra/Aragon Traveling to the mountainous regions of Spain rewards tourists with sweeping views and a connection to nature. —Spain Tourism, Miami Herald, 12 Nov. 2025

Breezy winds and falling temperatures will push wind chills near or below zero in mountainous areas overnight. —Sirena Bergman, MSNBC Newsweek, 10 Nov. 2025

This mountainous region is known for its lush forests, lakes and valleys – and for being a hotspot for this year’s deadly bear attacks in Japan. —Jessie Yeung, CNN Money, 7 Nov. 2025

Nestled within the Blue Ridge Mountains of western North Carolina, Boone’s endless mountainous views and lush green spaces create an instant sense of calm. —Essence, 7 Nov. 2025

Word History

Etymology

Middle English mounteynous, borrowed from Anglo-French muntaignus, from muntaigne, mountaigne mountain + -us -ous

First Known Use

14th century, in the meaning defined at sense 1

Kids Definition

mountainous

adjective

moun·​tain·​ous ˈmau̇nt-ᵊn-əs 

-nəs

1

: having many mountains

2

: resembling a mountain : huge