What's the Difference Between the Adjectives 'Adverse' and 'Averse'?

The words adverse and averse are related, but they don't have the same meaning.​ The adjective adverse means harmful, unfavorable, or antagonistic. Often it refers to conditions or things rather than people.

The adjective averse means having a feeling of opposition, distaste, or repugnance. As Kenneth Wilson points out in the usage notes below, we're most often "averse to (rarely from) things and people we dislike."

Examples

• "It is the adverse effect of television viewing on the lives of so many people that makes it feel like a serious addiction."
  (Marie Winn, The Plug-In Drug: Television, Computers, and Family Life, 2002)
• "Your friend Mr. Caldwell has some very singular adverse notions about poor abused John Calvin."
  (John Updike, The Centaur, 1963)
• "Finding that Ewell was averse to making an attack himself, averse to leaving Gettysburg; that Hill was averse to putting his crippled corps forward so soon again; and that Longstreet was averse to fighting at all on that ground, Lee may well have thought that his generals were no longer what they had been."
  (Samuel Adams Drake, The Battle of Gettysburg, 1891)
• "We have become a risk-averse culture in which our anxieties dictate our decisions in a totally disproportionate way."
  (Julian Baggini, "The Fear Factor." The Guardian, March 21, 2008)

Usage Notes

• "We’re most often adverse to actions, events, and things (which we most frequently describe as adverse or designate as adverse forms or adversities). We’re averse to (rarely from) things and people we dislike, but we almost never speak of an averse thing or person."
  (Kenneth G. Wilson, "adverse, averse," The Columbia Guide to Standard American English, 1993)
• "In summary, adverse and averse are only synonymous when used of persons and with to. Adverse is most often used as an attributive adjective and of things; averse is extremely rare as an attributive and is regularly used of persons. . . . Our evidence suggests averse to is more frequently used than adverse to."
  (Merriam-Webster's Concise Dictionary of English Usage, Merriam-Webster, 2002)

Practice

(a) "I didn't like the play, but then I saw it under _____ conditions: the curtain was up."
(Groucho Marx)
(b) "Schuyler was a sensitive and retiring woman who had been _____ to publicity all her life."
(Stuart Banner, American Property, 2011)

Answers

(a) "I didn't like the play, but then I saw it under adverse conditions: the curtain was up." (Groucho Marx)
(b) "Schuyler was a sensitive and retiring woman who had been averse to publicity all her life."
(Stuart Banner, American Property, 2011)