montainous

Adjective

mountainous (comparative more mountainous, superlative most mountainous)

1. Having many mountains; characterized by mountains; of the nature of a mountain; rough (terrain); rocky.
   • [Water vapour bubbles] hit againſt the ſides of the more eminent and Mountainous Places, of the Globe, and by this Concuſſion are condenſed, and thus become heavier than the Air they ſvvom in, and ſo gleet dovvn the rocky Caverns of theſe Mountains, […]1705, George Cheyne, “Of the Existence of a Deity”, in Philosophical Principles of Natural Religion: […], London: […] George Strahan […], →OCLC, § XXIX, page 184
2. Resembling a mountain, especially in size; huge; towering.
   • But the added size did not give them an advantage this time. Not when Kanter and Adams, two mountainous players, could match the Knicks’ girth with their own.2016 November 28, Mike Vorkunov, “Despite Flash of Rose’s Prime, Knicks Are Dazed by Westbrook and Thunder”, in The New York Times, archived from the original on 08 Nov 2020
3. (figuratively) Very difficult.
   • As Brazil faced the mountainous task of completing an Olympic venue before the opening ceremony, Chinese netizens got busy molehilling a remark by a Rio construction manager about their China supplier.2016 August 4, “Off-hand remark in Rio chafes Chinese Net”, in Global Times, archived from the original on 07 Mar 2020
4. (obsolete) Inhabiting mountains; hence, barbarous.