動詞 vacillate:

1. be undecided about something; waver between conflicting positions or courses of action
   同義詞：hover, vibrate, vacillate, oscillate
2. move or sway in a rising and falling or wavelike pattern
   同義詞：fluctuate, vacillate, waver

形容詞 vacillating:

1. uncertain in purpose or action
   同義詞：vacillant, wavering