Is there a term for “neutral” words whose connotations are limited to being either positive or negative?

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.

I believe the type of semantic shift involved in the examples given in the original post is subjectification. In this process, the meaning of the word shifts towards a subjective sense from an earlier neutral sense.

Here is a definition of the term and an example from the works of Elizabeth Traugott (Professor Emerita of Linguistics and English, Stanford University):

In historical (or diachronic) linguistics, subjectification (also known as subjectivization or subjectivisation) is a language change process in which a linguistic expression acquires meanings that convey the speaker's attitude or viewpoint. This is a pragmatic-semantic process, which means that inherent as well as contextual meaning of the given expression is considered. Subjectification is realized in lexical and grammatical change. It is also of interest to cognitive linguistics and pragmatics (cf. Ronald Langacker and Elizabeth Traugott).

Traugott proposes that the epistemic adverb evidently, which initially meant 'from evidence, clearly' and later developed into a subjective adverb, underwent subjectification:

• "1429 Will Braybroke in Ess.AST 5: 298 Yif thay finde euidently that i haue doon extorcion
  

  • 'If they find from evidence that I have performed extortions' (MED)

• 1443 Pecock Rule 56: More euydently fals þan þis is, þer is no þing
  

  • 'There is nothing more clearly false than this' (MED)

• 1690 Locke, Hum. Und. II. xxix: No Idea, therefore, can be undistinguishable from another ... for from all other, it is evidently different ('evident to all', weak subjective epistemic) (OED)

• 20th c.?: He is evidently right (in the meaning 'I conclude that he is right'; strong subjective epistemic inviting the inference of some concession or doubt on speaker's part)"

Source: Wikipedia/Subjectification(linguistics)

Here is another example of a subjectification (of adjectives) from a paper of Traugott (Pragmatics and language change, Stanford University):

A modal domain in which subjectification has recently been identified is that of modal adjectives like essential and vital (Van linden 2009). These originated as non-modal adjectives meaning ‘being such by its true nature’, and ‘associated with life’; they both came to be used with dynamic modal meaning (necessity in the situation) and eventually deontic moral meaning. In the non-modal meaning the adjective is a classifier of the noun as in:

(10)   Those essentiall parts of his (‘God’) (1596 Spencer [van linden 2009: 78])

Van linden proposes that the key to the development of dynamic modal meanings was use with evaluative modification of the noun to which a particular feature is said to be essential:

(11)   It is an essentiall property of man truly wise, not to open all the boxes of his bosome
         (1618 Raleigh, Remains [OED; van linden 2009: 82])

The speaker’s subjective evaluation of the nominal became associated with the adjective and gave rise to meanings of potentiality, indeed necessity in the situation.

These examples overlap at the very least with, and are very probably examples of, the types of semantic shift known as amelioration and pejoration. The hedging is because articles tend not to clarify whether the old senses have to be considered obsolete for the terms to apply.

English Words: History and Structure By Donka Minkova, Robert Stockwell describes this process:

Has the reference of the word gone up, or down, in its social status and content? Rising in status is called amelioration (from Latin melior, 'better'). One classic example of a word that has risen in status is knight, which used to mean, quite simply, boy, manservant ...

[F]or some reason, words are more likely to lose their status and respectability in the language than to ‘go up in the world’. Note the social unacceptability, or near unacceptability, of poor, cripple, idiot ... we have replaced then with underprivileged, disabled, mentally challenged....

ThoughtCo has an article tracing the amelioration of the word 'nice'.

My answer was the first thought that came to mind, and searching for better alternatives eventually led me right back to it:

Loaded words or language. A technique of propaganda, in which words acquire emotional baggage that becomes reinforced with usage.

http://examples.yourdictionary.com/loaded-language-examples.html

Excerpted from the above source:

The noted writer George Orwell in discussion of using loaded language had this to say:

"The word Fascism has now no meaning except in so far as it signifies 'something not desirable.' The words democracy, socialism, freedom, patriotic, realistic, justice have each of them several different meanings which cannot be reconciled with one another. In the case of a word like democracy, not only is there no agreed definition, but the attempt to make one is resisted from all sides. It is almost universally felt that when we call a country democratic we are praising it: consequently the defenders of every kind of regime claim that it is a democracy, and fear that they might have to stop using that word if it were tied down to any one meaning."

Notice also that some of the words mentioned previously here, are on the list of loaded words given by this source:

• Terrible
• Phenomenon

Other good examples of suggestions given from this source:

• Bureaucrat
• Evolution
• Interesting
• Exploit
• Popular
• Historic
• Inferior
• Superior
• Provoke
• Government

Speakers or writers intentionally loading (emotionally, via psychological manipulations or maneuvers) formerly or normally neutral words or phrases with either extremely positive or negative connotations, and then reinforcing the usage of that sort of language -- creates "loaded language / words".

I've often seen the following words being intentionally "loaded" with emotional baggage:

• Christian
• American
• Feminism

And many others with political or cultural associations. I kept my examples to a bare minimum, because I'm sure everyone here can easily think of enough on their own.

According to the source (and I agree), not all loaded language is inflammatory in nature. Some of it serves quite the opposite rhetorical purpose: using emotionally charged language to irrationally bestow certain political associations or cultural traits with a sort of exaggerated praise or glory.

So the key to creating the propaganda device of loaded language is in methodically attaching strong emotional baggage (whether positive or negative) to ordinary language in common usage, for the purpose of causing gradual or eventual social or political change, or even sometimes to instigate outright upheaval. I would characterize it as a power ploy.

Of course, loaded language can and often is used in attempts to change individuals as well (rather than groups or whole societies). I'd still call that propaganda, though.