Teacher: Not right now.
Student: Man, you is fuckin' ignorant!
1. Having the lack of knowledge, or background/factual information of a particular thing in general. However, the effect in which this person will be proceeding with their "unproven knowledge" imbedded in their mind as if factual information, they, in turn, will plan on using it in the future to make false and incorrect statements based on what they didn't know about the particular thing, or may have heard as a majority of votes for.
And being ignorant does not mean stupid. There's a big difference between the two words.
2. Derek walked up to Shavam, noticing that he looked like he was from India, and asks him, "Are you Indian?" Shavam replies, "Yes." Derek then asks, "Say somethin' Indian." Shavam, confused, walks off. Kaitie, who was watching the whole conversation, walks up to Derek and tells him he is ignorant because of what he said.
3. Rebecca turned on a lamp and the bulb went out, so she went to get a new lightbulb, leaving the lamp switched to "ON". Freddy, her ignorant little brother, saw the bulbless lamp, and wondered what would happen if he stuck his finger in the lightbulb socket of the lamp, not knowing that he would get shocked.
Smart Person: Taco bell isn't spanish food, it's supposed to be Mexican food, and it's just sloppy fast food, if you want real mexican food check out a family owned resturant.