Origin and history of unrealize

c. 1600, "not real, not substantial, having appearance only," from un- (1) "not" + real (adj.). The meaning "impractical, visionary" is by 1660s. The slang sense of "wonderful, great" is first recorded 1965.

Unreal City,

Under the brown fog of a winter dawn,

A crowd flowed over London Bridge, so many,

I had not thought death had undone so many.

[Eliot, from "The Waste Land," 1922]

word-forming element of Greek origin used to make verbs, Middle English -isen, from Old French -iser/-izer, from Late Latin -izare, from Greek -izein, a verb-forming element denoting the doing of the noun or adjective to which it is attached.

The variation of -ize and -ise began in Old French and Middle English, perhaps aided by a few words (such as surprise, see below) where the ending is French or Latin, not Greek. With the classical revival, English partially reverted to the correct Greek -z- spelling from late 16c. But the 1694 edition of the authoritative French Academy dictionary standardized the spellings as -s-, which influenced English.

In Britain, despite the opposition to it (at least formerly) of OED, Encyclopaedia Britannica, the Times of London, and Fowler, -ise remains dominant. Fowler thinks this is to avoid the difficulty of remembering the short list of common words not from Greek which must be spelled with an -s- (such as advertise, devise, surprise). American English has always favored -ize. The spelling variation involves about 200 English verbs.