Please add a feature that will both, (a) warn you when you are creating a duplicate word or definition within the same set and (b) warn you when you are creating a duplicate word or definition in the same course - indicating which level the word or definition already appears.
Please also add a feature that will mark duplicate words or definitions that have already been created for cleaning up lists when or if you roll out this feature.
Thanks for reading my suggestion!
Only one quick thought.
If you create your course in a spreadsheet then do a temporary sort on the word column, it would reveal this by placing words together.
There may also be a formula to check this?
(This is what I would do to overcome this issue.)
That’s a good thing to do when preparing a course using a speadsheet.
Before temporarily reordering in alphabetical order, I would recommend inserting an extra column in the spreadsheet to label the original order of the rows - numbered 1, 2, 3 … That way, it’s easy to reorder the rows later, to get back to the original order (using the Excel Sort&Filter icon/function, or equivalent).
Also, it’s easier to use the ‘Custom Sort’ drop-down option within the Sort&Filter icon as it allows you to select the specific column you want to use for sorting, not just the first or last column.
I do a lot of this kind of thing while checking for duplicates, checking for typos and for disambiguating items.
That’s not helpful. I don’t want to have to use excel, that doubles the amount of work I have to do to make a vocabulary list. Also, I don’t have the pro version so it’s very difficult to do this. Also, I am terrible with excel, I would have a difficult time doing this.
Quizlet had this duplicate warning feature. I don’t see any reason why memrise couldn’t add this feature.
Your suggestion of using excel is not helpful to me at all, in fact, your comment detracts from my request by giving the memrise team the idea that my suggested feature is unnecessary. I don’t appreciate your comment at all.
Hi @nunuvyurbidniz, it’s probably less challenging than you think - this YouTube video explains the process pretty well. Any spreadsheet will work, not just Excel, and the process should save you a lot of time.
Preparing the course in a spreadsheet ensures back up!
And you could take it elsewhere if you ever have to.
I also use it to divide it up into chunks of say 15 for the levels.
I sometimes use a change in alphabet letter as the level change.
Or you may have a logical grouping per level.
Thanks @ian_mn, although I am an old hand at this and very tech savvy, I learned a few more tips! 
Just stop. I don’t want to use excel, if I wanted to do that I would have google searched how to do it. Using excel DOES NOT HELP ME FIX VOCAB LISTS IN MEMRISE!!! They are two completely separate programs. Your comments are not appreciated because they detract from my request. Your offering me a solution for how to check for duplicate words in excel. NOT IN MEMRISE.
Your comments are very much not appreciated because you might give the memrise team the impression that my feature request is unnecessary while you offer a solution THAT WILL NOT HELP ME FIND DUPLICATE WORDS AND DEFINITIONS IN THE MEMRISE APP.
@ian_mn and @DW7 I wish I could delete your completely unhelpful comments 
Could you please, delete your comments and post them somewhere else where people want help with excel? Not where this person is requesting a feature from the memrise team?!
I am so sorry you don’t find our comments helpful.
You asked a question and I stopped my learning to tell you what I do (and why).
Your comment and request is addressed to MemRise so I’ll tag them (again), although it may not be answered immediately - that’s why we tried to help you.
PS
You may wish to prefix your title with …
[Feature Request]
which I think is convention to address your question to MemRise rather than to the Community.
PPS
Your Feature Request is a good one.
I added the tag you suggested, but this post was definitely posted in the ‘feedback and feature request’ section of the forum. Not the community in general.
after a small amount of reading through the forums, it seems that memrise only wants to push their own courses and they have disabled support for user created custom courses anyway?
Hi @nunuvyurbidniz,
Thanks for your comments on this. We’ve recorded this (internal code QA-758) and will take your feedback into consideration for any changes we may make to the course-creation system in the future.
Remember to keep things friendly on the forum 
others are only trying to help! Additional comments may also be useful for other users searching the same topic in the future. If you’d prefer to share your thoughts with us privately, you can do so here: https://memrise.zendesk.com/hc/en-us
Kind regards,
Memrise team
Hi @nunuvyurbidniz,
Just a thought …
If you’re planning on moving your Memrise courses to Quizlet, you could use tech189’s Memrise Scraper on-screen application (see below) to ease the transition by generating a tab-separated text file for each of your Memrise courses - this would save you re-typing everything.
https://tech189.dev/memrise/
No, I have been using Quizlet, and I recently switched to memrise because the ads on Quizlet have gotten so obnoxious it’s no longer a useful study tool. I’m trying to find a new app for studying Korean vocabulary. I’m just having a really hard time finding one that has all the features I would like. Memrise doesn’t do pure flash cards (or duplicate warnings). Vocabulary miner and anki have little to no variety of questions types (also no duplicate warnings).