persuade: [16] The -suade element of persuade goes back to Latin suādēre ‘advise, urge’, a descendant of the same Indo-European base (*swād-) as produced English assuage [14], suave [16], and sweet. Addition of the intensive prefix per- produced persuādēre, source of English persuade; while negation of suādēre with dis- has given English dissuade [15]. => assuage, suave, sweet[persuade etymology, persuade origin, 英语词源]