Students are commonly taught that these words should be distinguished from one another, with aggravate used to mean “to make worse, more serious, or more severe”1(p24) and irritate to mean “to provoke impatience, anger, or displeasure in.”1(p663) However, aggravate has been used to mean irritate since at least 1611 (in a dictionary, no less: Randle Cotrave’s A Dictionairie of the French and English Tongues)2 and moreover has been used in that sense by such writers as Cheever, Cowper, Dickens, Melville, and Styron.3
Despite that sterling track record, by 1870 the use of aggravate to mean irritate had for some reason begun to provoke finger-wagging,1(p24) and currently such use is more acceptable in conversation and casual writing. (Perfectly understandable, really: who has time to stop and ponder which is correct, when one’s meaning seems clear enough using either word?) On the other hand, more formal writing—perhaps because the reader has the benefit of neither nonverbal cues nor personal acquaintance with the writer—often calls for more precision, and published writing commonly preserves the distinction between these words.1(p24) Hence, many guides to written English continue to maintain that aggravate should never be used to mean irritate; for example, regarding such usage, Bernstein pointedly maintains that “neither the commonness nor the long history of misuse makes it any better than inept.”4
However, even writers who freely use aggravate in place of irritate do so only when describing a mental state—specifically, when someone or something is getting on one’s last nerve. Descriptions of physical states are another matter: while aggravate was used at least as early as the 1800s to indicate physical irritation (“With stinging wood smoke aggravating the eyes”),2 precision mandates that that the distinction between the words be preserved in such contexts. For example, a patient with conjunctivitis does not have an “aggravation of the conjunctiva”; irritation, or a reaction to a stimulus, is the finding here, although the patient might be advised that environmental irritants such as smoke can further aggravate the irritation already present (see §11.1, Current and Preferred Usage of Common Words and Phrases, in the AMA Manual of Style, pp 381-405 in print).
The bottom line:
●Describing a physical finding or state? In casual as well as formal contexts, current usage calls for irritate, with aggravate used only to describe the worsening of the irritation.
●Describing the effects of irksome behavior or circumstances? The use of aggravate to mean irritate is usually acceptable in casual communications and is rapidly gaining acceptance in more formal contexts as well, but persons writing for publication might be wise to use aggravate only to refer to a worsening of one’s irritation. On this point, Bernstein again: “[t]hose who say they are aggravated are, most likely, the same persons who say that in the hospital they were diagnosed.”4—Phil Sefton, ELS
1. Merriam-Webster’s Collegiate Dictionary. 11th ed. Springfield, MA: Merriam-Webster Inc; 2003.
2. Aggravate. The Compact Oxford English Dictionary. 2nd ed. Oxford, England: Oxford University Press; 1991:28.
3. Aggravate. Merriam-Webster’s Dictionary of English Usage. Springfield, MA: Merriam-Webster Inc; 1994:49.
4. Aggravate. In: Bernstein TM. The Careful Writer: A Modern Guide to English Usage. New York, NY: Athaneum; 1985:30.