I know this one is unpopular, and I know why.
When you've lived with a pattern of behaviour for years, having a word for it is a relief. It may be the first thing that made your experience make sense. Being told not to use it can feel like being told the experience doesn't count.
It does count. It just doesn't belong in the document.
What the reader sees
Not a diagnosis. A parent diagnosing the other parent.
Professionals in family proceedings are trained to be wary of exactly that, and it's one of the fastest ways to be seen as the high-conflict parent yourself. The label also does no work: you can't evidence it, and it invites an argument about terminology instead of facts.
The same goes for "alienator", "abuser", and any syndrome you've read about.
Do this instead
Describe the behaviour, with dates and sources:
On 14 March, the agreed handover time was changed by message 40 minutes beforehand. That was the fourth time in six weeks.
That sentence does everything the label was trying to do. And it can't be argued with, only checked.
Let the pattern speak
A reader who reaches a conclusion themselves holds it far more firmly than one who's been handed it. Lay out the dated facts and let them get there.
Keep the word for your own understanding, where it may be genuinely useful. Keep it out of anything a professional will read, because in that room it works against the very point you're trying to make.
If you have concerns about abuse or your children's safety, speak to a lawyer or a domestic abuse organisation about how to raise them properly. That's a different situation from the one this guide is about.
General information, not legal advice. Court process differs between countries and regions; check anything that matters to your case with a qualified lawyer where you live.
Chapter 14 of the workbook covers why labels backfire and what to write instead. Chapter 2 turns the patterns you've lived with into specific, trackable categories, so you have the dated behaviour to describe in place of the word.
See the workbook & spreadsheet