1. in a way that cannot be felt or touched; imperceptibly

Examples

• The fog rolled in impalpably, so gradually that no one noticed the exact moment it arrived.
• Time passed impalpably during the long meditation session.
• The influence of the ancient culture spread impalpably through the region over centuries.
• She felt the change in his mood impalpably, sensing something was wrong without any obvious sign.
• The boundary between day and night shifts impalpably as dusk approaches.