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

The Subject and the Study Site The parrot, named Bruce, is an endangered kea found in 2013 by bird expert Raoul Schwing in mountainous Arthur’s Pass, New Zealand. —Samantha Agate, Charlotte Observer, 22 Apr. 2026

In a country already running a third of global hydropower capacity, ambitious dam projects are breaking ground in China’s mountainous west, while the government has set its sights on pioneering next-generation technologies like nuclear fusion and green hydrogen. —Simone McCarthy, CNN Money, 21 Apr. 2026

Flights along the route must first navigate out of Denver’s mountainous landscape before landing among the Teton Range in Grand Teton National Park as Jackson Hole's airport remains the only commercial airport that sits within a national park in the country, per the National Park Service. —Michael Cappetta, Travel + Leisure, 21 Apr. 2026

Along the way there are medical emergencies, a drug trip, a private jet to a private Hot Chip concert somewhere mountainous and snowy, some unpleasant business with a dog, heartfelt conversations and existential crises. —Robert Lloyd, Boston Herald, 19 Apr. 2026

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