mountainous

adjective

moun·​tain·​ous ˈmau̇n-tə-nəs 

ˈmau̇nt-nəs

1

: containing many mountains

2

: resembling a mountain : huge

mountainously adverb

mountainousness noun

Synonyms

• astronomical
• astronomic
• Brobdingnagian
• bumper
• colossal
• cosmic
• cosmical
• cyclopean
• elephantine
• enormous
• galactic
• gargantuan
• giant
• gigantesque
• gigantic
• grand
• herculean
• heroic
• heroical
• Himalayan
• huge
• humongous
• humungous
• immense
• jumbo
• king-size
• king-sized
• leviathan
• mammoth
• massive
• mega
• mighty
• monster
• monstrous
• monumental
• oceanic
• pharaonic
• planetary
• prodigious
• super
• super-duper
• supersize
• supersized
• titanic
• tremendous
• vast
• vasty
• walloping
• whacking
• whopping

Examples of mountainous in a Sentence

the seemingly mountainous obstacles he had to overcome while growing up

Recent Examples on the Web

Omani culture also thrives in atmospheric souqs (markets), ancient forts and quiet agricultural villages tucked away in the country’s mountainous interior, an easy drive from Muscat. —Natasha Amar, Forbes.com, 11 May 2025

Nagorno-Karabakh Known as Artsakh to Armenians, Nagorno-Karabakh is a mountainous region in the South Caucuses that has been at the center of a decades-long dispute between Armenia and Azerbaijan. —Mandy Taheri, MSNBC Newsweek, 10 May 2025

About 62% of residents in the state’s rural, mountainous counties did the same. —Phillip Reese, Los Angeles Times, 9 May 2025

Jentzsch says there’s a limit to how much rice Japan can produce given its mountainous landscape. —Miranda Jeyaretnam, Time, 8 May 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