curable adj.

late 14c., "to restore to health or a sound state," from Old French curer and directly from Latin curare "take care of," hence, in medical language, "treat medically, cure" (see cure (n.1)). In reference to fish, pork, etc., "prepare for preservation by drying, salting, etc.," attested by 1743. Related: Cured; curing.

Most words for "cure, heal" in European languages originally applied to the person being treated but now can be used with reference to the disease. Relatively few show an ancient connection to words for "physician;" typically they are connected instead to words for "make whole" or "tend to" or even "conjurer." French guérir (with Italian guarir, Old Spanish guarir) is from a Germanic verb stem also found in in Gothic warjan, Old English wearian "ward off, prevent, defend" (see warrant (n.)).

common termination and word-forming element of English adjectives (typically based on verbs) and generally adding a notion of "capable of; allowed; worthy of; requiring; to be ______ed," sometimes "full of, causing," from French -able and directly from Latin -abilis. It is properly -ble, from Latin -bilis (the vowel being generally from the stem ending of the verb being suffixed), and it represents PIE *-tro-, a suffix used to form nouns of instrument, cognate with the second syllables of English rudder and saddle (n.).

A living element in English, used in new formations from either Latin or native words (readable, bearable) and also with nouns (objectionable, peaceable). Sometimes with an active signification (suitable, capable), sometimes of neutral signification (durable, conformable). It has become very elastic in meaning, as in a reliable witness, a playable foul ball, perishable goods. A 17c. writer has cadaverable "mortal."

To take a single example in detail, no-one but a competent philologist can tell whether reasonable comes from the verb or the noun reason, nor whether its original sense was that can be reasoned out, or that can reason, or that can be reasoned with, or that has reason, or that listens to reason, or that is consistent with reason; the ordinary man knows only that it can now mean any of these, & justifiably bases on these & similar facts a generous view of the termination's capabilities; credible meaning for him worthy of credence, why should not reliable & dependable mean worthy of reliance & dependence? [Fowler]

In Latin, -abilis and -ibilis depended on the inflectional vowel of the verb. Hence the variant form -ible in Old French, Spanish, English. In English, -able tends to be used with native (and other non-Latin) words, -ible with words of obvious Latin origin (but there are exceptions). The Latin suffix is not etymologically connected with able, but it long has been popularly associated with it, and this probably has contributed to its vigor as a living suffix.

"beyond the power or skill of medicine," mid-14c., from Old French incurable "not curable" (13c.), from Late Latin incurabilis "not curable," from in- "not" (see in- (1)) + curabilis "curable" (see curable). As a noun, "incurable person," from 1650s. Related: Incurably.