It's implied that the centaurs, who are deeply distrustful of humans, will hold her captive and possibly punish her for her actions.
Here's what we know and can infer:
* The centaurs don't kill her: Though they're furious with Umbridge, they don't seem interested in killing her. Instead, they capture her and take her to their forest.
* Umbridge is seen as a threat: The centaurs believe Umbridge's presence in the Forbidden Forest was dangerous and disruptive to their way of life.
* The centaurs might have different punishments: The centaurs are a proud and independent group. They might have their own way of dealing with Umbridge, possibly involving some form of magical confinement or even ritualistic punishment.
* Umbridge's fate remains uncertain: J.K. Rowling has not explicitly revealed Umbridge's fate after the centaurs take her, leaving it to the reader's imagination.
It's worth noting that the centaurs are not explicitly known for being cruel. They are more likely to use their knowledge of the forest and their own brand of justice to deal with Umbridge. However, the exact nature of this punishment remains unknown.