At current, it’s impossible to just mouse over a word without breaking flow of whatever I’m watching. I want to be able to just mouse over a single word I dont know, and get its definition without that dreadful moment where the window pauses itself and now I’m not longer watching a french show in french and following the language, the tone, the movements, absorbing the language at a comfortable pace. I’m a guy staring at a screen in silence looking at french definitions whos just had his momentum and immersion broke. 
Does it pause immediately for you on hover? For me, it is just the auto-pause feature that is toggled when hovering.
I have not yet reached your level of flow for Chinese, so I very much appreciate that the video automatically pauses just when the subtitle is about to disappear if I am hovering over a word and unpauses when I move away the pointer. If I hover, read and quickly move the pointer away, I guess I can read the definition without the video pausing, but I am rarely that fast.
There might be a work around for you. I get the same definition, but styled differently if I hover on the same word in the subtitle list to the right of the video. Then it does not pause the video. However, if you remove the subtitle list for an even more full immersion experience, then obviously this doesn’t work for you.