Mountain

An elevation of land of considerable dimensions rising more or less abruptly, forming a conspicuous figure in the landscape, usually having a small extent of surface at its summit.

"We spent the weekend hiking in the mountains."

Something very large in size or quantity; a huge amount; a great heap.

"He was a real mountain of a man, standing seven feet tall."

Of, belonging to, relating to, or found on a mountain; like a mountain in size; (of living things) growing or living on a mountain.

"some mountain ranges; the high mountain top; a scenic mountain view; the mountain lodge; the leaves of mountain cranberries; a mountain goat"

A difficult task or challenge.