If you accidentally deleted a word list from your Phrasebook on macOS, want to restore it, and feel a bit adventurous, there's a not very trivial way to do so. Yes, unfortunately, Mate doesn't trash items. There's always a security prompt, though, when you want to remove important data.
So, here's what you can do:
1. Download Realm Browser
2. Open Finder
3. Press shift + command + G
4. Paste ~/Library/Containers/andriiliakh.Instant-Translate/Data/Library/Application Support/ and press "Go"
5. Open "default.realm" with Realm Browser
6. Select "WordList" on the left
7. If your deleted list is present there – scroll to the right and untick the "isDeleted" field.
8. Close the Realm Browser and check Mate, the list should re-appear there.
This is not guaranteed to work.