If someone said this about a conversation

[thedaywewillremeber]

That the other person went in on them. What would you take this to me?

I take it to me the other person went on.

That they were harsh and didn't hold back.

That the other person verbally attacked them in some way.

Went in on = had a go at

I've never heard it before, but interrupted or verbally had a go at them? I'd need to know the context fully.

Had a go at

Agree with pps....went in is have a go at that person in a quite specific and hurtful way

It could be that the other person interrupted and either finished the person's story/explanation themselves in a group setting - taking over the conversation for attention or they thought they knew what the other person was saying and impatiently finished/concluded the conversation because they thought the original talker was taking too long/being unclear.

They were cutting in.

I have no idea? Never heard the expression before, but at a guess, I'd say verbally had words with them??? Was there more to the conversation? Is English their 1st language?

I would assume they told them off or harangued them, or were verbally aggressive in some way. ‘Went on at them’ is entirely different.

Went on at = talked too much for too long
Went in on = a telling off/aggressive in some way

Went in - had a go at them
Went on - talked too much

To me, went on at implies having a go at length. Went in on I have never heard before. Is it regional?

Went in on = attacked.

Scottish p here. I know of the term. First few posters are correct in saying it means that they verbally attacked them, were overly harsh and got personal, didn't hold back etc.

Never heard of it.

verbally laid into someone