phobia

First recorded in 1780–90; extracted from nouns ending in -phobia

See -phobia.

From Latin, from Greek, equivalent to -phob(os) “panic fear” + -ia noun suffix; see origin at -phobe, -ia

Normal fears can be adaptive for survival and evolution. Fearing animals or dangerous natural environments can inform behaviors that keep people safe. However, when a normal fear becomes extreme, out of proportion to the stimulus, persistent, or irrational, it is considered a phobia. Specific phobias are named with a root that describes the trigger stimulus, plus the combining form -phobia. Some of these -phobia words are well-known: arachnophobia, claustrophobia. Others are novel combinations that use the common combining form -phobia to name uncommon fears: alliumphobia, xocolatophobia. Despite knowing that their fear is disproportionate or irrational, people with a specific phobia have uncontrolled physical reactions including rapid heartbeat, trembling, sweating, and difficulty breathing.
There is another category of words that use the combining form -phobia to simply make antonyms of words that use the combining form -philia to describe affinity, love, or attraction, as Anglophobia versus Anglophilia. These -phobia words are not associated with a physical fear response. Instead, they indicate an aversion or distaste: ergophobia, sitophobia.
In many cases, these words indicate intolerance toward a group of people as defined by nationality, ancestry, sexual identity or orientation, creed, or race: homophobia, transphobia, Islamophobia. Though there is an element of fear when interacting with the unknown or the Other, words in this category are not primarily about anxiety; rather, they are commonly associated with hostility. The use of -phobia words to describe negative attitudes toward groups of people is therefore frequently criticized. Advocates and activists representing these groups recommend using the prefix anti- instead, in words such as antigay, antitrans, anti-Islam.

C19: from Greek phobos fear

via Latin from Greek, from phobos fear