Keen, lively, outwardly expressed eager interest or excitement for something..
Keen, lively, outwardly expressed eager interest or excitement for something.
The prototypical keen, lively, warm eager interest — positively valenced and outwardly expressed. Broader and milder than zeal, which implies energetic, unflagging pursuit and can tip into fanaticism; more energetic and expressive than the quieter interest or curiosity. Unlike hope or anticipation it is not directed at a future outcome but felt about something present or proposed; unlike eagerness (impatient readiness to act) it centers on admiration and excitement.
From Greek enthousiasmos “divine inspiration,” from entheos “possessed by a god” (en “in” + theos “god”). Entered English c. 1600. The literal root is “having a god within.”
A strongly documented shift: originally religious (divine possession), it acquired a derogatory sense under the Puritans — “excessive religious emotion, fanaticism” (1650s) — before the now-dominant positive “fervor, eager interest” by 1716. The secular-positive sense has been stable for ~300 years.