A Case of Mistaken Identity: Word pairs that are deceptively different

by: Kurt Woock

The English language is rife with confusing words. In English classes, you likely studied various categories of linguistic confusion: homophones, heteronyms, homonyms, synonyms, antonyms. At the root of the confusion is the fact that words can have a lot in common, to the extent they deceive writers and readers into thinking the words are interchangeable.

Sometimes, a group of words signify a similar meaning, but with differing gradations or levels of emphasis. Those subtle differences allow writers to express nuance and help bring clarity to writing. Using these words incorrectly might blur the author’s true intent, but it won’t substantially alter the meaning.

However, in some cases, despite the similarities between words, an impassable chasm exists between the two meanings. Using these words interchangeably does alter the sentence’s substance.

Here are four word pairs that are commonly mistaken as synonyms when, in fact, each word expresses a distinct idea:


Impact and its variations (impacted, impacting, etc.) have become some of the most ubiquitous buzzwords today. You’ll see it (mis)used in writing of all types. In most cases, effect is the better option.

Impact, whether used as a noun or a verb, means the moment two objects collide. It means strong, often violent force. Strictly speaking, its scope in time is limited to the very moment of…you guessed it…impact.

Effect is a broader term that means the consequences or results stemming from an action. Rather than focusing tightly on the singular moment in which a sudden change occurs, it is oriented toward changes that occur after the initial point of inflection, and without any cap on time.

Consider this sentence: “The group will study the impact the construction will have on the neighborhood.”

In this case, effect would be a better choice. Construction does not collide with anything, nor is it sudden or violent. Instead, the author intends to say something about resulting changes (whether short-, medium-, or long-term) that will occur because of the construction.


Although has a meaning similar to “despite that fact that…”. Often it is used to dispel a possible assumption the reader might have.

Example: Although I like most vegetables, I don’t like peas.

The word doesn’t give most people problems, but it’s important to understand the particulars of although because its cousin, while, tends to trip up writers. While is a function of time. It shows that two events occur concurrently:

Example: I went to the park while I was on lunch break.

Try substituting the word “when” for while whenever you use it. If the sentence still makes sense, you’re likely using while right.

While is often used where although would be a more precise choice. Oddly enough, you’ll rarely see although as an incorrect substitution for while…perhaps an indication that the two aren’t interchangeable.

Here’s a sentence in which although would have been a more precise choice:

While the Broncos are a very good football team this year, I still think the team from ’98 could beat them.

Here’s a similar sentence in which while is perfectly fine:

While the Broncos are taking the field for the first time this season, their fans are surely going to be loud.


Because shows causation or association. Use if you can replace with “as a result of the fact that…”.

Example: Because I live in Denver, I can easily go to the mountains.

Example: I need a lawyer because I am in trouble.

Since shows that a period of time has elapsed.

Example: It’s been five years since I’ve been to Texas.

The two words, side by side:

1. Since you’ve been gone, I can breathe for the first time.
2. Because you’ve been gone, I can breathe for the first time.

These two samples show how a sentence’s meaning can change, depending on word choice. In the first example, using “since” shows that the writer is emphasizing the time that has passed between two events (and is not necessarily the cause of either). The person who has vacated the author’s presence might or might not be related to the increase in the author’s ability to breathe. The departure is simply something used to mark time. Perhaps the other person’s departure simply coincided with the opening of a few windows. You likely hear similar constructions daily: “Since lunch, my phone hasn’t stopped ringing”; “I haven’t been able to concentrate since I woke up.” In both these cases, the writer is trying to define a period of time, not a cause.

In the second example, “because” suggests that the breathing is directly related to the person leaving.


When you were a child, you probably learned the difference between “may” and “can”. In recent years, OLLS has emphasized understanding the particular nuances of the terms “may”, “must”, and “shall” to express statutory requirements more clearly. However, the distinction between “may” and “might” is discussed less frequently.

May is best used to show that an action is dependent upon someone first granting permission. Take the following sentence:

“You may go on a short vacation during session if you are on top of your workload.”

Might is best used to show that a particular outcome, situation, or action comes about by chance.

The sentence “It might rain today” expresses might correctly. To say “it may rain today” would be incorrect. The rain does not occur because of any rational actor’s choosing, nor does it occur because it was given permission to do so.

Sometimes, both words can make sense in a sentence. However, this does not mean that both sentences mean the same thing. For example:

Alice may vote.

Alice might vote.

In the first example, the writer is expressing that Alice meets all the requirements to vote: She is 18, etc. However, it technically says nothing about the likelihood that she will do so. She might just stay home and watch TV. The second sentence considers just that—the chances that she’ll vote.

Use the distinctions found among these words to make your writing as clear as you can. Although we can write well, we don’t always. While we write, we too often choose the first word that comes to mind. We may choose whichever words we want, but we might not always choose the best ones. Because we strive to write as clearly as possible, we must be aware of this. Since you began reading this article, perhaps you’ve become more aware of the unintended effects that words such as “impact” can have.