Is it a stretch though? If one is impressed by something, then one might have something to say about it too, so having nothing to say (being nonplussed) becaus

Is it a stretch though? If one is impressed by something, then one might have something to say about it too, so having nothing to say (being nonplussed) because of being unimpressed... That is, if being unimpressed generally leads to one being nonplussed, then maybe being unimpressed can be expressed as being nonplussed.