vacillate
C2Formal
Definition
Meaning
To waver in mind, will, or feeling; to hesitate in choice of opinions or courses.
To fluctuate or sway physically; to swing back and forth indecisively between different opinions, courses of action, or states.
Linguistics
Semantic Notes
The word implies prolonged indecision or oscillation between options, not a momentary pause. It often connotes a lack of resolve or firmness in character.
Dialectal Variation
British vs American Usage
Differences
No significant difference in meaning or usage. Spelling and pronunciation are consistent.
Connotations
Equally formal in both dialects.
Frequency
Slightly more common in written, especially academic or political, discourse than in everyday speech in both regions.
Vocabulary
Collocations
Grammar
Valency Patterns
vacillate between A and Bvacillate on/over/about somethingVocabulary
Synonyms
Strong
Neutral
Weak
Vocabulary
Antonyms
Phrases
Idioms & Phrases
- “[Not strongly idiomatic; the verb itself is used]”
Usage
Context Usage
Business
Describes indecisive leadership or unstable market positions (e.g., 'The board vacillated on the merger for months.').
Academic
Used in political science, psychology, or history to describe policy indecision or fluctuating public opinion.
Everyday
Rare in casual conversation; might be used humorously or critically about someone's prolonged indecision.
Technical
Can be used in physics or engineering as a less common synonym for 'oscillate.'
Examples
By Part of Speech
verb
British English
- The government has vacillated over the new railway funding for years.
- He vacillated between ordering the fish or the vegetarian option.
American English
- The committee vacillated on the policy change until the deadline passed.
- She vacillated for weeks before accepting the job offer.
adverb
British English
- [The adverb 'vacillatingly' is grammatically possible but extremely rare and unnatural.]
American English
- [The adverb 'vacillatingly' is grammatically possible but extremely rare and unnatural.]
adjective
British English
- [Direct adjective form 'vacillant' is obsolete and not used.]
American English
- [Direct adjective form 'vacillant' is obsolete and not used.]
Examples
By CEFR Level
- [Too complex for A2; use simpler synonym 'cannot decide']
- It's hard to plan when you vacillate so much.
- Public opinion began to vacillate as more news about the scandal emerged.
- He vacillated between moving to London or staying in Manchester.
- The minister's vacillating response to the crisis undermined her authority.
- Investor confidence vacillated wildly with each new economic report.
Learning
Memory Aids
Mnemonic
Think of a VACUUm cleaner that can't decide which way to go, so it VACILLATES back and forth on the carpet.
Conceptual Metaphor
INDECISION IS PHYSICAL SWAYING/BACK-AND-FORTH MOTION.
Watch out
Common Pitfalls
Translation Traps (for Russian speakers)
- Do not confuse with 'vacation' (отпуск). The Russian 'колебаться' is a direct equivalent. Avoid calquing as 'vacillate between' when a simple 'не мог выбрать между' is more natural in many contexts.
Common Mistakes
- Incorrect preposition: 'vacillate with' (use 'between' or 'on'). Confusing with 'ventilate'. Using in overly informal contexts where 'can't decide' is better.
Practice
Quiz
In which context is the use of 'vacillate' LEAST appropriate?
FAQ
Frequently Asked Questions
No, it is a formal word most common in written English (news, academia, literature) and educated speech. In everyday conversation, people usually say 'can't decide', 'waver', or 'keep changing my mind'.
'Hesitate' is a momentary pause before an action, often due to doubt or fear. 'Vacillate' implies a longer period of going back and forth between different options or opinions.
Yes, but this is a secondary, less common usage. It can describe something swinging or swaying unsteadily (e.g., 'The needle vacillated before settling on the measurement'). The primary meaning is always mental/emotional indecision.
The most common noun is 'vacillation'. 'Vacillator' (a person who vacillates) is also possible but rare.