BLANK-VERSE, n. Unrhymed iambic pentameters — the most difficult kind of English verse to write acceptably; a kind, therefore, much affected by those who cannot acceptably write any kind.

Ambrose Bierce (1842-1914?) American writer and journalist

“Blank-verse,” The Cynic’s Word Book (1906)
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Included in The Devil's Dictionary (1911). Originally published in the "Devil's Dictionary" column in the San Francisco Wasp (1881-05-14). In that version, it included the final sentence:

Of all English and American poets not a half-dozen have been able to write good blank-verse; and the six hundred Californian poets are not among them.