What is the comparative and superlative of brilliantly?

"Brilliantly" is an adverb, so it doesn't have comparative and superlative forms in the same way as adjectives do.

To express different degrees of brilliance, you would use adverbs like:

* More brilliantly (comparative)

* Most brilliantly (superlative)

You could also use other adverbs to convey the same meaning, such as:

* More dazzlingly

* More splendidly

* More remarkably

* Most dazzlingly

* Most splendidly

* Most remarkably

For example:

* "The first performance was brilliant, but the second was more brilliantly executed."

* "Of all the dancers, she performed most brilliantly."