Mad (adjective)

1. Having a mental disorder; insane.
2. Extremely angry; furious.
3. Excited; frenzied.
4. Very enthusiastic about something.

Origin:

From old english 'gemædde' (out of one's mind), from 'gemaedde' (being out of one's mind), from 'maedan' (to rage).

Examples:

1. She went mad after she heard the news.
2. I was mad when I found out that he had lied to me.
3. The fans went mad when their team scored the winning goal.
4. He's mad about motorcycles and owns several of them.
5. She's a mad scientist who loves to experiment with chemicals.