General Opposites:
* Clear-headed
* Composed
* Lucid
* Sharp
* Alert
* Understanding
* Enlightened
More Specific Opposites:
* Informed (if befuddled refers to a lack of understanding)
* Calm (if befuddled refers to confusion and agitation)
* Certain (if befuddled refers to uncertainty)
Example:
* Befuddled: "He was completely befuddled by the instructions."
* Opposite: "She was clear-headed and understood the instructions perfectly."