Mount Everest vs Everest

Mount Everest and Everest both are nouns.

Word	Noun	Adjective	Verb	Adverb
Mount Everest	Yes	No	No	No
Everest	Yes	No	No	No

As nouns, Mount Everest and Everest are synonyms defined as:

Mount Everest and Everest: a mountain in the central Himalayas on the border of Tibet and Nepal; the highest mountain peak in the world (29,028 feet high)

Other synonyms of Mount Everest include Mt. Everest.

Mount Everest (noun)	Everest (noun)
a mountain in the central Himalayas on the border of Tibet and Nepal; the highest mountain peak in the world (29,028 feet high)	a mountain in the central Himalayas on the border of Tibet and Nepal; the highest mountain peak in the world (29,028 feet high)