The word appears 4 times.
This novel takes place during WWII and there is an incident at the airbase involving a man from Texas accused of being a racist.
"You murdered him," said Dunbar.
"You killed him," said Yossarian.
The Texan shrank back. "You fellas are crazy. I didn't even touch him."
"You murdered him," said Dunbar.
"I heard you kill him," said Yossarian.
"You killed him because he was a nigger," Dunbar said.
"You fellas are crazy," the Texan cried. "They don't allow niggers in here. They got a special place for niggers."
"The sergeant smuggled him in," Dunbar said.
"And you knew it."
Racial prejudice is a terrible thing, Yossarian. It really is. It's a terrible thing to treat a decent, loyal Indian like a nigger, kike, wop or spic. Cheif White Halfoat nodded slowly in conviction.