Is there a way to disable threat hints, which appear on the main screen when you examine enemy with mouse pointer?
No way to disable it per se, but you can replace these strings with empty text if you really wish to get rid of them.
Open file config/translate.json with text editor, e.g. notepad
Replace line "title" : "\n\n Threat: ", with "title" : "",
And same for each hint description, e.g. "Effortless", → "",
By the way, can you tell why you want these hints to be removed?
Thanks 
By the way, can you tell why you want these hints to be removed?
Just wanted VCMI to look more similar to original HOMM3.
I really appreciate VCMI team efforts, but this is not the QoL-thing I’d prefer use.