How to translate undermine

Undermine (lessen the effectiveness, power, or ability of, especially gradually or insidiously), as in:

"That undermines my parenting."
"Don't undermine my parenting."

There isnft one word that is completely equal to that in Japanese.
So you are a parent, and you are trying to tell someone who is doing something with your child that would render your parenting efforts useless, like grandmother/neighbor trying to give your child some sweets while you are trying to keep sweets only as treats on special occasions, or something like that?
In Japanese it could come out quite blunt, like gdonft get in the way of my parentingh or gdonft bother me/intrude in my parenting,h or a bit lengthy but gdonft do things that would waste my parenting efforts.h
Depends on how blunt you want it:
- Watashi no kosodate no jama wo shinaide kudasai. (Please donft get in the way of my parenting.) – this can sound very blunt.
- Watashi no kosodate no doryoku wo muda ni shinaide hoshii no desu. (I donft want you/anyone to waste my parenting efforts.)
- Watashi ga shite iru koto wo muda ni shinaide hoshii no desu. (I donft want you/anyone to waste what Ifm doing.)

Thank you AK, that helps a lot. It's the child's grandparent.

Yes, it does sound blunt if I say "don't undermine my parenting." Even in English, it sounds quite blunt.

In English it can possibly sound more gentle if I say, "that undermines my parenting" and especially if the appropriate tone and facial/body language are used. But in Japanese, even if the tone/body language is gentle, using "that undermines my parenting," would the words themselves decidedly render the message as still being blunt?

In Asian cultures, I know the respect for elders is extremely important. Is this one of those cultural things that you just can't say without being disrespectful? Is this one of those things you just have to suck up and suffer?

OK, now I understand the situationc

First about wording things:
I guess, gplease donftch or gthat (what you do) underminesch would sound blunt, but they say convey what you are FEELING rather than ask what to do/not to do (generally speaking) in close relationships to get things understood.

Soc the last two sentences where I worded it to say gI donft want you toch gIfd rather not (anyone) have this donech are my attempts to do that, convey YOUR feeling/wish.
Also you could add that you are putting a lot of thoughts behind your parenting.

Watashi mo iroiro kangaete kosodate shite imasu. (Ifm putting a lot of thoughts behind my parenting.)
Then:
Watashi ga shite iru koto wo muda ni shinaide hoshii no desu. (I would not want you to waste what I am doing.)
Or (for the second sentence)
Watashi no doryoku ga muda ni naru you de, tsurai desu. (It feels like what Ifm doing is wasted, and it is painful.)
Or
Watashi ga shite iru koto wo muda ni shinaide kudasattara, ureshii desu. (Ifd be happy if you could refrain from wasting what I am doing.)

Parenting and grandparents:
When it comes to parentingc Ifm a Japanese woman, into my 50s with no kids, so I donft have firsthand experience with grandparents spoiling my kid(s), but I have heard stories about it from friends.
Some say, oh let them have their fun with the grand-kids, it wonft last long; others say stand firm when you canft stand it, say it blunt; others say let your spouse do the talking (if the spouse is on your side).
Some say no matter how you say it, they are going to say, oh so you are not happy about what we are doing, huh?? So it is better to just say what you want, it is YOUR child.

Without knowing you, your in-laws or relatives, I have no way to suggest anything, but I guess Ifd have just blurted out my thoughts, if I were in your shoes. You donft have to suck it up just because the grandparents are Asian/Japanese. Just my two cents.

AK, your posts are extremely helpful and I am very grateful that you took the time to answer and help me out. And I'm glad to know you don't think I have to endure this in silence just because I'm dealing with a grandparent who is Japanese. But yeah, conveying my feelings vs. being demanding will hopefully make the situation go smoother, so I will use your suggestions.

I have been doing this way. = I want to do this way.= your way is not same to my way. = your way is different from my way.= my way is different from your way. = you undermine my way. = your way is wrong. = etc...
there are a lot of expressions. but, it is better not to make the word "you" (or something related to "you") as the subject, especially in the cases when you have opinions different from them. @(probably by that reason, we use passive sentences more.)