Among the pairs of words that writers often confuse, affect and effect might be the most perplexing, perhaps because their meanings are so similar.
Affect, derived from affectus, from the Latin word afficere, “to do something to, act on,” is easily conflated with effect, borrowed from Anglo-French, ultimately stemming from the Latin word effectus, from efficere, “to bring about.”
What’s the difference between affect and effect?
Affect is usually a verb, meaning to influence or act upon. Example:
The loss of his father affected him profoundly.
Effect is usually a noun, meaning the result of an action. Example:
What will be the effect of closing Main Street?
Below you will find less-common meanings and related or derivative words.
The various senses of affect, each followed by a sentence demonstrating them, follow:
- A noun meaning “mental state”: “In his report, the psychiatrist, noting his lack of expression or other signs of emotion, described his affect as flat.”
- A verb meaning “to produce an effect, to influence”: “I knew that my opinion would affect her choice, so I deliberately withheld it.”
- A verb meaning “to pretend” or “to put on”: “She tried to affect an air of nonchalance, though she was visibly agitated.”
Words with affect as the root, followed by their use in a sentence, include the following:
- Affectation: A noun meaning “self-conscious behavior”: “The girl’s affectationof sophisticated maturity was undercut by the relentless snapping of her chewing gum.”
- Affection: A noun meaning “kind or loving emotion”: “Her grandfather’s deep affection for her was obvious in his heartwarming smile.”
- Disaffected: An adjective meaning “discontented, rebellious”: “Disaffectedyouth dismayed by the poor job market and the larger issue of a society that does not seem to value them have been joining the protest movement in ever greater numbers.” (This word is a case of an antonym that has outlived the original term from which it was derived in counterpoint; writers and speakers no longer express, in the sense of “favorably disposed,” that a person is affected.)
- Unaffected: An adjective with two distinct senses: the literal meaning of “not influenced or altered” (“They seemed disturbingly unaffected by the tragic news”) and the surprisingly older, figurative meaning “genuine” (“The youth’s candid, unaffected demeanor appealed to her after the stilted arrogance of her many suitors”).
The various senses of effect, each followed by a sentence demonstrating them, follow:
A noun meaning “the result of a cause”: “The effect of the lopsided vote was a loss of confidence in the chairman.”
A noun meaning “an impression”: “The soft, gentle tone has a calming effect.”
A noun, usually in plural form, meaning “personal property, possession”: “Among the effects found in the deceased man’s pockets was a small book with his name self-inscribed.”
A verb meaning “to accomplish”: “His newfound sense of responsibility effected a positive change in her attitude toward him.”
Words with effect as the root, followed by their use in a sentence, include the following:
- Aftereffect: A noun, usually in plural form, meaning “something that follows a cause”: “The aftereffects of the decision are still being felt years later.”
- Effective: An adjective meaning “successful”: “The insect repellent was effective at keeping the mosquitoes at bay, which made for a pleasant outing.”
- Effectual: An adjective meaning “able to produce a desired effect”: “Our conclusion is that mediation is an effectual strategy for obtaining a mutually satisfying outcome.”
- The noun efficiency and the adjective efficient, though not based on the root effect, share its etymological origin and mean, respectively, “productivity” and “productive” in the sense of accomplishing something with a minimum of effort in relation to outcome. Efficacy (“the power to produce a desired effect”) and efficacious (“able to produce a desired effect”) are also related. Another, unexpected word of related origin is feckless (“weak, worthless”), which is rare and has lost its antonym, feckful, through long disuse. Feck is a shortened form of effect developed in Scottish English.
Quotations from newspapers
Consider these published applications:
…Tariff winners and losers: How Trump’s trade spat could affect shoppers. President Trump’s imposition of tariffs on imported … (www.usatoday.com)
… 405,000 years, gravitational tugs from the planets Jupiter and Venus gradually affect Earth’s climate and life forms, according to a new study.”… (www.usatoday.com)
… he says. “You can eat as much as you like, you can slob about, you can drink as much alcohol as you like – the effect is very modest compared with these other two factors.” Human beings are biologically engineered for … (www.theguardian.com)
…European Union tariffs take effect in Trump fight: How they will hit American products … (www.usatoday.com)
A rule of thumb is that affect is usually a verb (a “doing word”) and effect is usually a noun (something you can put “the” in front of).
This doesn’t apply all the time, of course; as we’ve seen above, there are lots of ways in which the words affect and effect can be used. It’s a good place to begin, though, if you’re unsure which you want.
Here’s a sample sentence:
I don’t think this will [affect/effect] the budget.
Which word, affect or effect, is correct?
An easy way to figure this out is to replace affect with the verb alter and see whether the sentence works:
I don’t think this will alter the budget.
Yes—it still makes sense, so affect is the word you want.
Here’s another sentence:
We haven’t yet experienced the full [affect/effect] of climate change.
Can we use affect here? Try replacing it with alter:
We haven’t yet experienced the full alter of climate change.
No, that doesn’t make sense at all.
How about effect? Try replacing that with end result:
We haven’t yet experienced the full end result of climate change.
It’s a slightly inelegant sentence, but it does work grammatically. So effect is the word you want here.
This rule won’t work for every single situation, but in most cases, it’ll help you quickly select the word that you want.
What about affect as a noun and effect as a verb?
It’s fairly rare to come across affect used as a noun: As we saw above, when it is used in this way, it means “mental state.” You might encounter it in older works or scientific tomes about psychiatry.
It’s a little more common to come across effect used as a verb, though this is still fairly rare and it can seem a little old-fashioned in this context. It’s used to mean “brought about” or “accomplished”—e.g., “The rapid changes she made after she got the job effected a complete turnaround in the company’s financial position.”
In any case where you’re uncertain, though, it’s likely that affect is a verb (replace it with alter to check) and effect is a noun (replace it with end result to check).