slew vs mountain

slew and mountain both are nouns.

Word	Noun	Adjective	Verb	Adverb
slew	Yes	No	Yes	No
mountain	Yes	No	No	No

As nouns, slew and mountain are synonyms defined as:

slew and mountain: (often followed by `of') a large number or amount or extent

slew (noun)	mountain (noun)
(often followed by `of') a large number or amount or extent	a land mass that projects well above its surroundings; higher than a hill
	(often followed by `of') a large number or amount or extent

slew (verb)	mountain (verb)
turn sharply; change direction abruptly
move obliquely or sideways, usually in an uncontrolled manner