My understanding of it is:
Blanket hatred, condemnation, and hate speech targeting all things/people Jewish.
My grandfather tried to indoctrinate me into this way of thinking, and when I kept trying to pin him down with asking him to explain WHY "the Jews were the most hated people in Europe"... the first time we discussed this, I wasn't even out of elementary school. I thought he was giving me a history lesson in a neutral way, as in "this is what some people in Europe thought" (because my grandfather was born in Norway to Swedish and Norwegian parents, so of course he knew more than I did about Europe).
Fast-forward a bunch of years, and I started to wonder if he himself hated Jews.
Then along came Jim Keegstra, a high school social studies teacher who indoctrinated his students to hate Jewish people. He force-fed them every nasty thing he could, including Holocaust denial and the idea that "even if the Holocaust happened, they deserved it." This went on for years, until finally parents started realizing what their kids were being taught. Keegstra went on trial in Red Deer (he taught in a town in Central Alberta, and lucky us, we were the nearest large city to handle this), and one of my college English instructors started defending him.
That English instructor tried to bring his pro-Keegstra stance into the theatre, as he was playing the male lead in the production of "Gypsy" we were doing that year. The producer and directors told him to leave Keegstra out of it - say NOTHING, don't wear pro-Keegstra stuff, don't talk to the child actors about it, just SHUT UP about it.
Well, he managed for awhile. Then one night we had a rehearsal in April and a huge dump of snow. I was bringing a couple of large bags of props to the theatre and he was pulling in to the parking lot. He got out and told me, "Keegstra would blame the Jews for this snow."
I told him I didn't want to hear it. He might have been one of my English instructors in college, but that didn't obligate me to listen to him outside the classroom. So when he kept trying to carry on, I told him, "I do not want to hear this. PERIOD."
As someone who has tried to rid myself of prejudicial attitudes (haven't succeeded with some of them, but who on this planet has?), it really annoys me when people try to indoctrinate others. As someone who spent time in the elementary education program in college (B.Ed.), I was appalled. You DON'T indoctrinate kids in bigotry. You just don't, no matter what level they're at.
Keegstra lost his teaching license and had to pay a fine. They could have chucked him into prison, and I wish they had. He went back to being a mechanic, and then got the bright idea to run for the Social Credit party in the next provincial election.
My grandfather perked up and said, "I'm voting for him!" Even after the disgrace of losing his teaching license, Keegstra still couldn't leave it alone. I listened to a speech he gave, and for the first 5 minutes, it was the kind of speech any political candidate would give. Then he veered back to his anti-Jewish ranting. I told my grandfather, "People aren't going to vote for him unless they're already bigoted. He will never be an MLA."
Well, that was in the 1980s. There are plenty of bigoted MLAs here nowadays. My own is among them. It's frustrating when Canadians online find out where I'm from and start to assume I'm like the government here, or the people who voted for them, and have had to modify my interactions with "I promise I didn't vote for the UCP".
My grandfather told my grandmother that it didn't matter that she said she would vote NDP, since his vote would cancel hers. I told him that my dad and I were also voting NDP, so it was 3 to 1. He didn't like that; he was "the boss" of the house, and we were all supposed to shut up and obey.
Well, I don't know who he voted for. I do know that neither my grandmother nor my dad agreed with this anti-semitic crap Keegstra was spewing. My grandfather never did understand the egregious way in which Keegstra betrayed his students. Some of them testified that they felt "messed up" and confused as to what to believe. To subject an essentially captive audience to this - those kids were required to conform to his beliefs in all their assignments and spew it back to him - is not education. It's brainwashing. It took some of those kids years to deal with it. Some never really did, reasoning that "a teacher told us this, and teachers don't lie." Well, yes, they sometimes do lie, and in some pretty horrible ways.
At one point my grandfather tried to convince me Keegstra was right, and I told him, "Look. If you hate the Jews, you need to stop watching Star Trek, T.J. Hooker, and everything else William Shatner is in. You also need to stop borrowing my science fiction books."
He demanded to know why, and I told him, "William Shatner is Jewish. So is Leonard Nimoy and about half the people who worked on Star Trek (Original Series at that time; this was pre-TNG). About a quarter to a third of the books in my science fiction collection were written by authors who happen to be Jewish. So if you hate Jews that much, you should stop watching TV and reading my books."
We finally agreed that if he wanted to talk about how he hated Jews and how "evil" they were, he could do it with his friends or whoever else would listen to him, because I wouldn't. I didn't want him to talk about that in my hearing, so I stopped hanging around when he had his conversations with the neighbors (usual thing was for people in the neighborhood with dogs to take their dogs for a walk and meet up and shoot the breeze for awhile).