The first South African convicted for racist slurs will serve her full three-year prison sentence after a court on Wednesday rejected her application to appeal.
Former realtor Vicki Momberg, 49, was last month convicted for repeatedly hurling racist insults including the word "kaffir" at a black policeman.
She was found guilty of crimen injuria -- wilfully hurting someone's dignity.
Magistrate Pravina Rugoonandan dismissed her appeal attempt, saying the sentence was "fair and just".
Momberg was caught on video verbally abusing the officer who was trying to assist her following a break-in of her car in 2016. She used the word "kaffir" 48 times.
The case was the first in South Africa to send a person to prison for crimen injuria. Previous convictions typically resulted in fines.
The word "kaffir" is "an embodiment of racial supremacy and hatred, all wrapped in one," the magistrate said.
"The K-word is unique in South African conscience and one which is so deeply linked with the painful past of emotional abuse, political violence and economic dispossession."
Momberg showed no sign of emotion as she was led back to the cells.
Her case turned the spotlight on racial divisions in South Africa a generation after the end of apartheid rule.
In 2016, another white real estate agent, Penny Sparrow, was fined $10,000 (8,000 euros) for likening black beachgoers to monkeys in a Facebook post.
About a dozen protesters in court on Wednesday wearing T-shirts with the slogan "we are one" applauded the ruling.
"Seven years would have been the most appropriate," said Simamkele Mabeta, 24, one of the protesters.
But Sharon Henderson, a sympathiser who handed Momberg a bottle of water during the hearing, said that the ruling is "really unfair".
"(The magistrate) accused her of being responsible of the whole of South Africa's race problems," she said.