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

Bordering Honduras to the south and Costa Rica to the north, Nicaragua shares aspects of both — mountainous terrain, defined dry and rainy seasons, the threat of hurricanes, and a challenging transportation network. —Lauren Mowery, Forbes.com, 22 May 2025

The villages in this mountainous landscape are home to a pastoral nomadic community that has lived for generations in close connection with the land. —Natela Grigalashvili, The Dial, 20 May 2025

Insects that live in mountainous areas have evolved ways to compensate for these environmental conditions. —Smithsonian Magazine, Smithsonian Magazine, 15 May 2025

Now a staple across the Coffee Belt, restaurants in Colombia’s mountainous regions offer calentados, sans leftovers. 6. —Cat Sposato, AFAR Media, 15 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