Clay Purvis, in Paula Fox's novel The Slave Dancer, can be defined as an ignorant man. In order to do so, and justify the characterization, one needs to understand what ignorant means.
Ignorant describes a person who generally lacks knowledge or awareness. That being said, ignorance is not always a negative word. One can use it to describe an ignorance regarding a specific subject outside of their own expertise or general knowledge. (For example, a history teacher may be ignorant of how to form compound chemical reactions.
As for Purvis, he can be seen as ignorant in a couple ways.
1. Pervis is uneducated. While this, alone, does not mean that he is ignorant, he is certainly ignorant of things which people learn when they are educated properly and/or formally.
2. Perivs is ignorant of how to be sympathetic. When Jessie is homesick, Pervis grabs him and shakes him. Instead of comforting him, the more typically accepted thing to do, Pervis believes that his actions are what are needed in order to comfort Jessie. He is certainly ignorant of sympathy.
Not only does Pervis show his ignorance of sympathy with Jessie, he also shows his ignorance of sympathy with the slaves. He does not believe them to be human.