mountain climber vs venturer

mountain climber and venturer both are nouns.

Word	Noun	Adjective	Verb	Adverb
mountain climber	Yes	No	No	No
venturer	Yes	No	No	No

As nouns, venturer is a hypernym of mountain climber; that is, venturer is a word with a broader meaning than mountain climber:

Other hypernyms of mountain climber include adventurer, climber.

mountain climber (noun)	venturer (noun)
someone who climbs mountains	a person who enjoys taking risks
	a merchant who undertakes a trading venture (especially a venture that sends goods overseas)