Context clues are wonderful things. With them, a writer can load an article with lots of unusual or unfamiliar words and not worry that a reader will misunderstand.

That’s good.

But if the context clues are unclear, a reader is going to stop and puzzle over the unfamiliar word.

That’s bad.

To start with, making the reader stop in the middle of a sentence is not a good idea. She might become distracted, never to return.

But if she does try to figure out the word, she’s going to go use the familiar and apply it to the unfamiliar. For example, if she sees the unfamiliar word “mythos,” she might conclude it has something to do with “myths,” and use that to understand the sentence. In that case, she’d be right. But that’s not always the case, and if she gets it wrong, the meaning of the sentence could be lost.

Take this example: “Director Yeatman, making his feature debut after a successful career as a visual effects expert, busies himself with the digital rendering (which is very well done) and as many in-your-face 3-D shots as he can muster. “G-Force” is the opposite of Pixar’s “Up” in this regard; if it’s not comin’ at ya, it’s not worthy of our attention. Despite this, the movie’s an enervating experience. You can take the whole family; I did.”

Now, of those of you who didn’t know what “enervating” means, do you understand it now?

Here’s another example: “That’s Mitchell all over. Despite an enervating two-hour practice Monday morning on the hottest day of camp thus far, Mitchell came for an interview chipper and grateful to have an opportunity to make an NFL roster.”

How many of you think that “enervate” has something to do with “energy”?

If it’s a lot of you, those were “enervating” examples, because “enervate” has nothing to do with “energy.” It’s related to “nerves,” and means “to deprive of strength, force, vigor, etc.; weaken physically, mentally, or morally; devitalize; debilitate,” in Webster’s New World College Dictionary.

Those examples, which used “enervate” correctly, included unclear context clues—nothing in those sentences absolutely supported or amplified the negative nature of “enervate.”

Here’s one that’s even farther afield:

“But the water in the river must first run the gauntlet of Las Vegas, literally floating that city’s needs so it can maintain the vitally important gambling and showbiz industry which enervates that state.” (Another “teachable moment” in that sentence, the use of “gauntlet,” has already been discussed here.)

In that example, all the clues pointing to “enervate” are positive. And since “enervate” is a negative word, the reader who tried to figure it out from the context clues and her familiarity with other words now has exactly the opposite impression.

The writer, too, may have misunderstood what “enervate” means. It happens enough that American Heritage includes a usage note about the confusion: “Sometimes people mistakenly use enervate to mean “to invigorate” or “to excite” by assuming that this word is a close cousin of the verb energize.”

Here are context clues that are unmistakable:

“While relationships are work, this just didn’t feel like it. It’s the kind of work that feels energizing rather than enervating,” one report said. In this case, contrasting the two words also gives readers instant reinforcement that these are two different words.

And in this example, all the surrounding images are “negative,” leaving the unmistakable impression that the unfamiliar word is negative, too:

“But on Tuesday, especially after meeting Congolese rape victims and touring a squalid refugee camp where thousands of people lived cheek by sunken cheek, Mrs. Clinton seemed enervated. Perhaps it was the sight of so many civilians suffering from a conflict the world has failed to stop.”

So get up the nerve to use unfamiliar words. Just don’t “enervate” yourself when you do.

Merrill Perlman managed copy desks across the newsroom at The New York Times, where she worked for 25 years.