General opposites:
* Solemnly: This suggests seriousness and gravity.
* Dejectedly: Implies sadness or discouragement.
* Dully: Lacking in energy or enthusiasm.
* Listlessly: Without energy or interest.
* Wearily: Showing tiredness or exhaustion.
More specific opposites:
* Clumsily: If jauntily implies grace and agility, the opposite would be clumsiness.
* Hesitantly: If jauntily suggests confidence, the opposite would be hesitation.
* Bluntly: If jauntily implies a playful or light-hearted manner, the opposite would be bluntness.
Example:
* Jauntily: He walked jauntily down the street.
* Solemnly: He walked solemnly down the street after receiving the bad news.
The best opposite will depend on the specific situation and the meaning you want to convey.