I've been wondering for some time now if there is an existing term for a rhetorical phenomenon I've noticed. It occurs when a word, instead of being used in its literal or etymological sense, is used only to refer to what is perceived as an especially "good" or "bad" manifestation of that sense. That's a bit obscure, I know. Let me move to concrete examples. Here's a partial list:
Classy/classical
Economical
Humane
Phenomenon/al
Predicament
Dilemma
Here's an analysis: "classy" or "classical", strictly and literally speaking, should refer only to something that is a member of a class in some way (in other words, practically everything). And yet, of course, that's not what those words mean: they refer to things that belong to the "highest" or a superior class, not just any class. "Economical" can refer to anything that has to do with managing money, but it's most commonly used only to refer to managing money well, i.e., being thrifty (cf. "economy-size"). "Humane" looks like it should refer to any behavior that's typical of humans, but it refers only to nice behavior typical of humans (bullies are acting in a very typically human way, yet we don't call them humane). "Phenomenon", in its original, philosophical sense, means more or less anything that appears to the senses. Yet we say Serena and Venus Williams are "phenomena" or that they're "phenomenal", as if that wasn't true of all humans and indeed all material objects.
On the "bad" side, a "predicament" used to mean (I quote Webster's) "a particular state, condition, or situation", derived from a philosophical term that described any class of things that could be ascribed or "predicated" to another class of things. Yet it has come to mean only (again I quote) "an unpleasantly difficult, perplexing, or dangerous situation". A "dilemma" is, literally, simply a choice between two options. Yet we most commonly use it to refer only to a difficult or unpleasant choice, or even more generally, any unpleasant situation or "predicament".
This sort of semantic shift seems to me to bear a family resemblance to synecdoche (in this case, using the whole to refer to a part), so my makeshift terms for these two phenomena have been "eusynecdoche" and "dysynecdoche" (i.e., "good" synecdoche and "bad" synecdoche). But these terms, besides being generally infelicitous, don't seem quite accurate to me: I'm not sure this is an instance of synecdoche. Every example of synecdoche I've ever seen uses a word to replace an entirely different word (using "hand" to refer to a sailor, for example). But this is just taking one limited sense of a word and using it as the only or primary sense.
Does anyone have any ideas, either about what this is called, or what it could be called, or whether it's even a thing at all?
Much gratitude in advance.