This one: 韵味蕴含 Context: His words seemed to 韵味蕴含 I know 蕴含 means hidden. And 韵味 can refer to charm of something. But it doesn't seem to make sense to me. Because in the story, this guy seemed to be threatening someone else politely. So I gather that maybe this idiom was put in there to convey that his polite words had some hidden meaning? But something still doesn't feel quite right to me. Help will be appreciated.
perhaps it could be something like his words carrying a hidden charm, which made the person he's threatening somewhat stunned or something along those lines
I don't think that is a "chengyu", a "chengyu" is a folk saying, like the English "baker's dozen" or "as the crow flies". This one is just "his words are full of hidden meanings" or basically sly implications. Something like "So, you know what your wife is doing right now don't you?". Basically unspoken implications.
I copied and pasted directly from the text. The author probably wanted to sound original or whatever, by rearranging the words.