vacillation vs irresolution

vacillation and irresolution both are nouns.

Word	Noun	Adjective	Verb	Adverb
vacillation	Yes	No	No	No
irresolution	Yes	No	No	No

As nouns, irresolution is a hypernym of vacillation; that is, irresolution is a word with a broader meaning than vacillation:

vacillation: indecision in speech or action
irresolution: doubt concerning two or more possible alternatives or courses of action

Other hypernyms of vacillation include indecision, indecisiveness.

vacillation (noun)	irresolution (noun)
changing location by moving back and forth	the trait of being irresolute; lacking firmness of purpose
indecision in speech or action	doubt concerning two or more possible alternatives or courses of action