intensify (v.)youdaoicibaDictYouDict[intensify 词源字典]
1817, from intense + -ify, first attested in Coleridge, in place of intend, which he said no longer was felt as connected with intense. Middle English used intensen (v.) "to increase (something), strengthen, intensify," early 15c. Related: Intensified; intensifying.[intensify etymology, intensify origin, 英语词源]