1. "Not exceptionally": In this case, the opposite would be exceptionally, meaning something is outstanding or unusual.
2. "In a way that is not exceptional": Here, the opposite would be exceptionally, meaning in a way that is outstanding or unusual.
Examples:
* Unexceptionally: The weather was unexceptionally mild for this time of year. (Meaning: The weather was not unusually mild.)
* Opposite: The weather was exceptionally mild for this time of year. (Meaning: The weather was unusually mild.)
* Unexceptionally: The presentation was unexceptionally boring. (Meaning: The presentation was not exceptionally boring, just average.)
* Opposite: The presentation was exceptionally boring. (Meaning: The presentation was unusually boring.)
Therefore, depending on the context, the opposite of "unexceptionally" is either exceptionally or exceptionally.