1. light; bright; well-lit; well-lighted
まだ明るいから怖い夢も見ないだろうし。Since it's still bright, I probably won't have any scary dreams either.
2. bright (colour)
明るい絵だった。It was a bright picture.
3. cheerful; bright; spirited; sunny (e.g. disposition)
みんなの顔が明るくなったよ。Everyone's faces brightened up.
4. bright (future, prospects, etc.); rosy; encouraging; promising
5. knowledgeable (about); familiar (with); well versed (in); well acquainted (with)
as ...に明るい
6. fair (e.g. politics); clean; impartial