My 4 1/2 Year Old Uses the Wrong Words When Angry.

I think you have already done the first part. I would keep an ear out for him using them again, and monitor what he sees on TV or hears on the radio as well. My DD picks up on things other family members think she doesn't hear -her room is not that far from the livingroom and if the TV is up...

I'd also work with him on how to express himself with different words. Use statements like "I don't like it when you take my toy." vs "You freak! Give me back my toy!"

As a preschool teacher, I would provide a lot of social coaching and try to move the children through the moment with empathy for both his anger AND the other child's feelings. This will be long, but since you asked, here's a script of what this might look like. (I'm adding generic "Tommy and Suzy" for clarity)

Tommy: You idiot! Go away from me!
Teacher: Wow, I see two kids who are pretty upset.
Suzy: Teacher, Tommy said I was an idiot!
Teacher: Yes, I see two kids who are really mad. (Still describing what I see.) Suzy, what happened? (I'm asking Suzy first, because she is less upset, not because she's 'the victim'. )
Suzy: I wanted to play with Tommy and he called names.
Teacher: Tommy, can you tell me what happened?
Tommy: I told Suzy to go away but she won't and she's not leaving me alone.
Teacher: So let me see if I have this right: Tommy, I understand you wanted to play by yourself. Suzy didn't let you and you got mad and called her a rude name. Is that correct? (recapping so that we are all on the same page and I know *I* didn't miss anything)
**Kids nod.**
Teacher: Suzy, did you like that Tommy was upset and using angry words with you?
Suzy: No.
Teacher: Then tell Tommy that.
Suzy: Tommy, I don't like when you use mean words at me. (they need tons of coaching at this, by the way)
Teacher: Tommy, did you hear what Suzy told you, that she doesn't like how you spoke to her?
Tommy: Yeah, but she wouldn't leave me alone.
Teacher: That's true too. Do you want to tell Suzy about it? What could you say in a friendly way?
Tommy: (either on his own or with coaching) Suzy, I don't want to play with you/ I don't want company right now.
Teacher: Suzy, did you hear what Tommy is telling you?
Suzy: But I want to play with Tommy.
Teacher: I understand this. You can say: "Tommy, I want to play with you when you are ready for company." This way he'll know.
Suzy: (repeats request)

This seems long and a bit pedantic, but this is what kids need- for everyone's emotions to be acknowledged and given a ton of social coaching. At this point, I would see if "Tommy" was ready to go back to what he was doing (with support from me to help Suzy understand she needed to leave him alone) or if I felt offering some quiet time in a cozy corner for Tommy was a better choice. I always had one or two spaces in my classrooms for independent, solo play, where kids could go to be alone. (we call them 'one player' areas) If Tommy was in a pretty grumpy mood, I'd invite him to go play in the cozy corner until he was ready for company. I remind children that the cozy corner is a place for just one person and that I will help them to be left alone if need be.

The Cozy Corner is a place for kids who need to be alone, to calm down, to rest... it's not a punishment. If we have a lot of hurtful words going on, perhaps we try the Cozy Corner first; if the language continues, then I get more direct and have a child sit in time out. I'm pretty clear that these words are 'mean and hurting words and they hurt just as much as hitting'. We pretty much reserve Time Out for aggressive hurting behaviors,spitting, or flat-out digging-in-the-heels noncompliance to directions; Time Out for hurtful language is also okay.

And as a mom, if my son is was using this language, I'd send him to his room until he was ready to use better words and was ready to be with company. He knows that this means his language/behavior is not welcome in the common areas of the house. "Come back when you are ready to talk about this in a calm way".

Give him other words to use instead.

You are bothering me.

Please leave me alone.
You are making me frustrated.

You are not listening to my words.

I want you to stop.

I do not like when you take my toys.

I do not like when you tell me what to do.

Let the teacher know you are working on it and when he uses these words to handle him the way they normally would for the use of bad words.

Right now these words are bad habits. You just need to give him some better words and praise him when he uses the correct words.

You and your husband need to model using better words also.

I agree with the others. My son loves saying the word poop and boobies. Eyeroll. LOL! I secretly agree those are just some classically funny sounding words and he could be using worse words, but we don't want him to talk that way in public. He is only allowed to use the word poop when he is referring to it as a potty term i.e. I pooped my pants, I have to go poop, etc. or as for booby if that area of his chest hurts or if we happen to be talking about duck-billed boobies! Ha! At any rate, we strive to give him examples to use the term in an appropriate way otherwise, we expand our vocabulary with other words to express ourselves. He does get a time-out for excessive use of bad words or putdowns and is redirected to use other funny words like shooby-dooby or caterpickles. These are some of our favorites that make us laugh. We are a bunch of goofballs over here. LOL
Just keep explaining to him why these words are not nice and give him other words to choose from. As he matures he will understand more and have better vocabulary to choose from. Hope this helps!
A.

I would just keep doing what you are doing right now - you've told him these words are not allowed and you've told him what he should say and do if other kids are bothering him. You may have to repeat yourself a number of times but hopefully it will eventually sink in. If after a week it's still an issue, you can sit down with him and explain that if you hear him use these words, or you get any more bad reports from the teacher, he may lose some privilege for a few days - TV, playing with a favorite toy, etc. But the teacher should also be able to discipline him in school as she sees necessary, since being disciplined for it right away (rather than hours later at home) may have more of an impact.

My 4 year old is a tape recorder and it's very hard to re-record over what he knows :). I said the S word one time in front of him and he said it for months. I had to change to saying Jiminy the Cricket and so now that's what he says too. But it took lots of times of me saying it for him to get that one.

Name calling is never acceptable...but kids are kids and they will do it.

I try to ask my 4 year old how he would feel if someone called him stupid, freak, idiot...etc. I tell him to make sure he only talks to people the way he wants to be talked to. If he feels like he is going to say something he shouldn't, he needs to walk away and take a break. He's getting much better at doing it on his own, but we still remind him to just walk away.

Give him alternative words to use.

When my son picked up a bad word, we told him to say something like "silly" instead.

aw sounds like my 3 y/o. Depending on when she uses them the punishment can range from no desert to timeout. Disney Movies are awesome for filling your kids with colorful words from shut up in Brother Bear, spoled little rich boy in princess and the frog to cry baby in Bambi 2. Your doing the right thing just keep at it