Definitions:

1. Changing location by moving back and forth. NOUN
   • The traveler's vacillation between two different routes delayed their arrival.
2. Indecision or the inability to make a firm decision. NOUN
   • The couple's vacillation over whether to have children strained their relationship.
3. Refers to the act of wavering between different opinions or actions. NOUN
   • The team's vacillation between attaching and defending resulted in a loss of momentum.

Synonyms:

• ambivalence
• apprehension
• hesitance
• hesitancy
• hesitation
• indecision
• insecurity
• lack of conviction
• pause
• reluctance
• swing
• uncertainty
• unsureness
• wavering