What word is the opposite of dull?

There are many words that could be considered the opposite of dull, depending on the context. Here are a few options:

General Opposites:

* Exciting

* Interesting

* Stimulating

* Engaging

* Vibrant

* Lively

* Intriguing

* Thrilling

More Specific Opposites:

* Sharp (for intellect)

* Brilliant (for light or intelligence)

* Sharp (for a blade)

* Shiny (for appearance)

The best word to use depends on the specific situation. For example, if you're talking about a person, "exciting" might be the best choice. If you're talking about a color, "vibrant" might be more appropriate.