Izable

Izable is a suffix used in English to form adjectives meaning “able to be” or “capable of being” the action described by a base verb, typically a verb ending in -ize. The suffix signals that the thing in question can undergo the action or meet the condition expressed by the verb. It is commonly attached to verbs formed with -ize, creating words such as "optimiz(e)able" or "realiz(e)able." The form has its roots in Latin and was transmitted through French as -isable/-izable.

Spelling and variants vary by dialect. In American English, the suffix is usually spelled -izable, as in realizable and customizable. In British English, the corresponding form is often -isable, as in realizable vs realisable, customizable vs customisable. Some words exist in both spellings with the same meaning, while others are predominantly used in one variant due to the root verb’s spelling (for example, recognize → recognizable vs recognise → recognisable). Both forms are widely understood and considered correct in their respective dialects.

Usage notes. -izable adjectives express potential to undergo the action of the root verb, but they are not always interchangeable with simpler -able or -ible adjectives. They tend to appear in formal or technical writing and in contexts involving assessment, design, or evaluation of processes and systems. Examples include customizable (able to be customized), recognizable (able to be recognized), realizable (able to be realized), prioritizable (able to be prioritized), and optimizable (able to be optimized). The choice between -izable and -isable depends on regional spelling conventions and the specific word’s established form.