vac ‧ il ‧ late /ˈvæsəleɪt, ˈvæsɪleɪt/ BrE AmE verb [intransitive] formal
[ Date: 1500-1600 ; Language: Latin ; Origin: past participle of vacillare 'to move from side to side, fail to decide' ]
to continue to change your opinions, decisions, ideas etc SYN waver
vacillate between
Her parents vacillated between different approaches to discipline.
—vacillation /ˌvæsəˈleɪʃ ə n, ˌvæsɪˈleɪʃ ə n/ noun [uncountable and countable]