Yes, you may use those words appropriately, which is to say in accordance with common usage, but do you really know what they mean?
Perhaps you do, but most people, it seems, do not. The Reuters headline: Horror film "Buried" an excruciating experience, for example, nicely demonstrates the incomprehending and absurd use of a multisyllabic Latinate adjective.
Excruciating is a word derived from the Latin ex, out of or from, and cruciare, to crucify. Now to be buried alive must certainly be horrific, but few would imagine it to be closely comparable to the torment of crucifixion. To be buried alive is to be cast into darkness, crushed and suffocated. To liken live burial with crucifixion thus robs the word excruciating of useful meaning. It makes it merely another in a long list of rather meaningless intensifiers, its only merit being its multisyllablicity, to coin a term, that makes it hiss, pop and slither off the tongue.
Abject is another term largely robbed of useful meaning by constant ill-informed use. "Abject poverty," scores about half a million hits in Google, with "abject failure" not far behind. But the word is derived from the Latin abjectus, meaning cast out, which is to say, rubbish. So for once, Reuters had it right in the headline: Cricket — Abject England humiliated by Netherlands, which is to say, "England were rubbish."
Lurid means, as the folks at Reuters seem entirely unaware:
wan, or ghastly pale, or any of several light or medium grayish colors, etc., etc.So Reuters rob the term of any useful meaning in their headline Closing arguments begin in lurid N.H. murder trial, a trial that was, to judge from the Reuters report, very far from wan, or ghastly pale. However, by sheer accident, Reuters almost got it right with the headline: "Ghost writers" wrote lurid claims: Paul campaign except that they applied the word to the wrong object. It was the ghost writers who one might suppose were wan or ghastly pale in any of several light or medium grayish colors, i.e., lurid, not the claims which were distinctly colorful.
The debasement of language due to the imprecise or incorrect use of words results from the fact that few English speakers today know Latin, whereas much of the literature remains the work of classically trained writers. The result is that most educated English speakers are familiar through wide reading with polysyllabic Latinate words, but are without much idea of what those words mean. They understand them only from the context, which results in the smearing out of meaning to virtual nothingness, or in the case of most adjectives, mere synonymity with very,* preferred only because they sound somehow more expressive. Such words have, as Mr. Polly might have said, "verbojuice," but add little meaning.
Since, today, teaching everyone Latin is inconceivable, the solution to the problem of the misuse and abuse of multisyllabic Latinate terms is, I think, to avoid their use use altogether, instead choosing what are generally shorter Anglo-Saxon words that everyone understands. This was the advice of that winner of the Nobel Prize for literature, Winston Churchill, who at school failed to understand the need for Latin, but learned very well how to write a plain English sentence. Modified according to Churchill's rule, the cricket headline: Rubbish England Humiliated by Netherlands is clear and forceful, whereas the original Abject England Humiliated by Netherlands is both limp and obscure.
* Very is a word that
Germanic and Latinate equivalent words in English