How to say you don't want to renew friendship?

Don't think there is such a thing mosaicwarts It will be kinder in there long term to be honest with the person concerned and say you have moved on now.
Cruel to be kind comes to mind.

Just keep saying it's not a good time. Be unavailable, leave texts, calls, emails unanswered.If your doorbell goes,have a peek, if it's them don't answer. If they turn up at your door say " oh, Im sorry Im just heading out to an appointment, meeting with ..... " . If it gets really bad tell them you are going on a long holiday.

I understand your dilemma and personally I think the trick is simply to continue to be unavailable: block his number and if he contacts you in other ways simply say it's not a good time and that you will contact him when it's convenient.

We had someone years ago who was thick skinned and insistent. I just said “no, I really don’t want to thanks” and if pushed “why” said “sorry, I don’t want to talk about it”, or “I feel that it’s not for me” or similar. Something that can’t be argued with. And if challenged said “ I can’t help the way I feel, I’m sorry, the answer is still no”.
After maybe 3 or 4 attempts they gave up.
Once you give a reason, thick-skinned people will have a counter-one.

Stop replying, a little harsh but sometimes necessary, best wishes

Just have your coat on ready if it's them at the door .
I do that if Jehova's Witnesses appear.

I think you need to tell them. Tell them what you've told us. Write them a letter maybe.

Don't ghost them though. That's infuriating and could possibly make him more determined

The trick with Jehova´s Witnesses apparently is to say that you have already found God and worship in your own way. Best really, to say you are Jewish, they will run a mile. Not that that helps the OP.

This is difficult but if they really won't take a hint I would just say that you don't have time for them in your life as things have moved on. Not much else you can do if they are that thick skinned.

Thank you very much for taking the time to reply.

I've been on my own for three and a half years, somehow I feel more vulnerable now than I was in the beginning. This person definitely abused my kindness and made a fool of me in the community.

Fiachna50, I thought he'd come round last year and hid in the larder for about 15 minutes with the doorbell going ... ha ha, it was my son's friend, same colour car!

Have a good evening

Don’t worry too much about the “nicely” part of it.
Be unavailable/out/busy/block him on your mobile or leave voicemail messages unanswered

This person has appeared after years? You owe him/her nothing. Don't reply to emails etc. Block them on your mobile/Facebook etc. Don't reply to any calls.

Just tell him that period was a very difficult time in your life and you have moved on and would rather not rekindle a friendship that reminds you of that period

That he was the cause of your difficulties doesn't need to be said.

Or

as others have suggested just block them, put thebphone on answerphone and do not reply.

mosaicwarts, you don't have to reject this person 'nicely'.
They are thick skinned and probably wouldn't "get it" anyway.
I would, as others have mentioned, ignore them but if they still persist, you might have to tell them that you are sorry but you really don't want to be friends with them.
After this message or email, totally ignore any replies.

After such a long time maybe he is after something again and has run out of folks to use Like others have said, refuse and ignore. I would.

"no" is a complete sentance.
But if you want to expand on it: "No thank you, that wouldnt work for me (/suit me/appeal to me)"

I had a similar situation with one of my first husband's friends. He kept ringing up (often at mealtimes) and asking to meet up. It was one of the few times I regretted having kept the same landline number after two house moves.

In the end, polite excuses just weren't cutting the mustard so I was just really blunt and said "No, you were a complete c*nt then, you're clearly still a complete c*nt who can't take the hint and I'd rather pull out my toenails with rusty pliers than see you again" & hung up. Other expletives are available but sometimes needs must when the devil drives, or has rung a dozen times.

He's not bothered me since.

Saying 'now is not a good time' leaves an opening to a thick skinned person to keep trying. Assert yourself the very next time he asks and say a very firm 'no thank you, I don't want to'. Prevaricating will only prolong the agony.

Have you any reason to believe that he wouldn't automatically distance himself from you if you told him the truth? Because if he's thick skinned, persistent and manipulative telling him that now isn't a good time is just like telling him that later is-

I agree with SpringyChicken!

LondonGranny, I am all admiration. That is the sort of response I think of afterwards. You go girl. ????

I will remember that Londongranny. Directness. No wonder he didn't return. I think women are very vulnerable after losing their husbands/partners. An old friend of mine who was widowed once warned me that she felt her husbands passing left her vulnerable and that some not all people were worth the watching. I think she meant they would take advantage re money etc given the chance. I do know she lost money 'leant' to a friend. It took her a couple of years to really be herself again, she missed her husband very much.

I wouldn't have second thoughts of just putting the phone down and block the calls.
Life is too short to put up with a pain the the A* human being.

Brilliant! That’s exactly the thing to do!

Laughed so much I’ve got coffee streaming through my nostrils spilt my drink