The revolting forces were just barely held at bay.

The revolting forces were just barely held at bay.

What is the meaning of the above sentence?

“revolting forces” = forces (probably military forces or similar) who were “revolting”, that is, trying to overthrow a ruler. (Care is needed when using “revolting” like this because the common meaning of “repulsive / extremely unpleasant” tends to dominate.)

“held at bay” = kept at a safe distance; prevented from succeeding in their attack (“hold at bay” is a set expression)