intensity (n.)youdaoicibaDictYouDict[intensity 词源字典]
formed in English 1660s from intense + -ity. Earlier was intenseness (1610s). Sense of "extreme depth of feeling" first recorded 1830.[intensity etymology, intensity origin, 英语词源]
tense (adj.)youdaoicibaDictYouDict
"stretched tight," 1660s, from Latin tensus, past participle of tendere "to stretch, extend" (see tenet). Figurative sense of "in a state of nervous tension" is first recorded 1821. Related: Tensely; tenseness.