dangerous undertaking vs risky venture

dangerous undertaking and risky venture both are nouns.

Word	Noun	Adjective	Verb	Adverb
dangerous undertaking	Yes	No	No	No
risky venture	Yes	No	No	No

As nouns, dangerous undertaking and risky venture are synonyms defined as:

dangerous undertaking and risky venture: a wild and exciting undertaking (not necessarily lawful)

Other synonyms of dangerous undertaking include adventure, escapade.

dangerous undertaking (noun)	risky venture (noun)
a wild and exciting undertaking (not necessarily lawful)	a wild and exciting undertaking (not necessarily lawful)