Also ef‑ and e-.
Out; upward; thoroughly; removal or release; former.
Latin ex, out of.
This prefix is common, appearing in a variety of verbs, adjectives, nouns, and the occasional adverb. However, virtually all instances have been derived from Latin sources, mostly verbs, that already contain the prefix. Apart from its hyphenated form meaning ‘former’ (see below), it has only rarely been used in English to create new words.
In verbs, the most common sense is a literal or figurative one based on the meaning of its Latin source, as in exclude (Latin excludere, from claudere, to shut) or export (Latin exportare, from portare, carry); it may suggest a figurative movement upwards, as in exalt (Latin exaltare, from altus, high); sometimes it expresses the idea of thoroughness, as in excruciate (Latin excruciat‑, tormented, based on crux, cruc‑, a cross), or making something worse, as in exacerbate (Latin exacerbat‑, made harsh, from acerbus, harsh, bitter); it may suggest removal or release, as in excommunicate (ecclesiastical Latin excommunicat‑, excluded from communication with the faithful, from communis, common to all); it may suggest the inducement of a state, as in exasperate (Latin exasperat‑, irritated to anger, from the verb exasperare, derived from asper, rough).
Other verbs containing various of these senses are: excel, excuse, extend, export, express, and extort. Some examples of adjectival forms are exorbitant, exquisite, extant, extinct, and extravagant. Nouns include example, exertion, exhilaration, expert, expletive, explosion, and exploration.
In hyphenated words attached to names of offices or functions, it means ‘former’: ex-wife, ex-mayor, ex-president, ex-serviceman, ex-parrot.
The spelling ex‑ appears in Latin before vowels; before f it becomes ef‑: effervesce, effigy, effort, effusive; before consonants it becomes e‑: ebullient, edict, elect, emaciated, enormity, erupt, escape.