mountainous

1 of 2

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

mountainousness

2 of 2

noun

moun·​tain·​ous·​ness

plural -es

: the quality or state of being mountainous

Synonyms of mountainous

Adjective

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

Examples of mountainous in a Sentence

Adjective

the seemingly mountainous obstacles he had to overcome while growing up

Recent Examples on the Web

Adjective

This is what happened in the Big Thompson back in 1976, when slow-moving thunderstorms dumped copious amounts of rain over mountainous terrain. — Dave Aguilera, CBS News, 31 July 2026

But a worrying number of young people have also needed rescuing from mountainous regions. — Lea Tran, TheWeek, 30 July 2026

Saturday's Stage 20 took riders along some mountainous roads, and where there are mountains there are often cliffs. — Matt Reigle Outkick, FOXNews.com, 25 July 2026

The Global Financial Crisis had saddled GE Capital, long its biggest profitmaker, with mountainous debt. — Shawn Tully, Fortune, 23 July 2026

Word History

Etymology

Adjective

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

First Known Use

Adjective

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