vacillator
/ˈvæsɪˌleɪtər/Definitions
1. noun
a person or thing that vacillates; someone who hesitates or is indecisive
“The politician’s decision to run for president was delayed due to a vacillator on his campaign team.”
2. noun
a device or mechanism that varies or oscillates, especially one that controls the movement of something
“The engineer adjusted the vacillator to fine-tune the robotic arm’s motion.”