Q: My understanding is that the “-able” or “-ible” suffix refers to a passive condition, the ability to have something done to it. Good air is “breathable,” food is “edible,” etc. In television commercials, though, I hear “breathable” used for fabrics that “breathe.” Should I be bothered by this?
A: “Breathable” can go either way because it has both active and passive meanings—capable of breathing as well as fit to be breathed.
When first recorded in 1731, “breathable” was used passively and meant fit to be breathed or inhaled.
This 19th-century citation in the Oxford English Dictionary is a good example: “How breathable the atmosphere!” (from Blackwood’s Magazine, 1839).
In the mid-20th century, people began using “breathable” in an active sense to describe material or clothing that, in the OED’s definition, “admits air to the skin and allows sweat to evaporate.”
Oxford’s earliest citation is from a 1937 issue of the Hammond (Indiana) Times: “Breathable suede jackets. Water repellent. They’re new!”
Later on, the verb “breathe” itself was used in reference to such nonliving things as uncorked wine (1950s) and materials that let air pass through (1960s).
Naturally these things weren’t actually inhaling; they were said to “breathe” because they absorbed air or allowed it to move freely.
But returning to your question, it’s not true that adjectives ending in “-able” and “-ible” are always used in a passive sense or in reference to a passive condition.
Some denote a capacity for being subjected to something (passive), while others denote a capacity for doing something (active). Not many of these adjectives do both, like “breathable.”
Examples of passive adjectives include “credible” (said of something that can be believed), “audible” (something that can be heard), “preferable” (a thing that’s to be preferred), and “bearable” (something can be borne).
Examples of the active ones include “comfortable” (said of something that comforts), “durable” (a thing that endures), “horrible” (something that horrifies), and “possible” (a thing that can happen).
You may be curious about why some of these adjectives end in “-able” and some in “-ible.” The reasons are rooted in Latin, where verbs with different endings were given different adjectival suffixes (-abilis or -ibilis).
Both kinds of endings passed on into Old French (-able, -ible), but the distinction became muddled when French replaced most of the –ible endings with –able.
The result is that English has both kinds of “-ble” adjectives, but as we wrote in a blog post in 2007, the “-able” words far outnumber the “-ible” words. It’s easy to see why.
For one thing, most of the “-ble” adjectives that English acquired from French end in “-able.”
So do most of those that were formed from native English words. So if a word existed in Old English and later formed one of these “-ble” adjectives, it’s probably an “-able” (like “knowable,” “walkable,” “foreseeable,” “drinkable,” “unspeakable,” “doable,” etc.).
In fact, new adjectives formed in modern English, despite their etymological roots, almost always end in “-able,” like “danceable” (first recorded in 1859), “buildable” (1927), “microwaveable” (1977).
All things considered, it’s a wonder we have as many “-ible” adjectives as we do.
Finally, a point that may surprise you. The suffix “-able” is no relation to the adjective and adverb “able.” So resist the temptation to interpret every “-able” adjective in terms of “able to,” especially the passive ones.
Strictly speaking, “unspeakable,” means unfit to be spoken of, not unable to be spoken of. “Drinkable” means “fit to drink,” not “able to be drunk.” And “eatable” means “fit to be eaten,” not “able to be eaten.”
Though both have come down from Latin, the word “able” and the suffix “-able” are etymologically unrelated.
The word “able” ultimately comes from the verb habere (to hold). The suffix “-able,” as we mentioned, comes from the Latin suffix –abilis, which was used to forms adjectives from verbs ending in –are.
But, as the OED says, an “early association with the adjective able” probably encouraged the notion that a word like “eatable,” with its “-able” suffix, “could be reapprehended as ‘able to be eaten.’ ”