1. in a way that changes quickly and unpredictably; with volatile or fickle behavior

Examples

• Her mood shifted mercurially from joy to anger within minutes.
• The stock market moved mercurially throughout the trading day.
• He spoke mercurially, jumping from topic to topic without warning.
• The weather changed mercurially, making it impossible to plan outdoor activities.
• She mercurially abandoned her original plan and chose a completely different approach.
• The politician’s positions shifted mercurially depending on his audience.