Clear And Steady

He that uses words without any clear and steady meaning, what does he but lead himself and others into errors?  And he that designedly does it, ought to be looked on as an enemy to truth and knowledge.

-- John Locke (1632 - 1704), English philosopher and social contract theorist, An Essay Concerning Human Understanding (1689), Book III, Chapter XI "Of the Remedies of the Foregoing Imperfections and Abuses of Words"