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

Where to stay Time to head north – more specifically Sapa, the mountainous region close to Vietnam’s border with China. —Tamara Hinson, Condé Nast Traveler, 27 Mar. 2026

Adding garlic reflects traditional recipes from Lebanon’s mountainous regions, while pomegranate molasses (a popular addition in Syria), gives depth and robust sweetness to the zingy sumac dressing. —Rebecca Firkser, Bon Appetit Magazine, 25 Mar. 2026

Some of these weather threats will reach into Iran, where some of the mountainous regions of the country might see some snow. —Daniel Manzo, ABC News, 24 Mar. 2026

Hailing from mountainous southwestern Virginia, the Stanley Brothers – Ralph and Carter – were a foundational act in bluegrass whose music has influenced generations of artists in a variety of genres. —Chris Willman, Variety, 20 Mar. 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