General Antonyms:
* Mourn: To feel or express sorrow or grief.
* Sympathize: To share in the feelings of another, especially sorrow or grief.
* Console: To comfort someone who is sad or disappointed.
* Empathize: To understand and share the feelings of another.
Antonyms Specific to the Context of Gloating:
* Regret: To feel sorry for something that has happened.
* Apologize: To express regret for something wrong you have done.
* Humility: The quality of being humble; not proud or arrogant.
* Modesty: The quality of being unassuming or moderate in the estimation of one's abilities.
The best antonym for "gloat" depends on the specific context.