Definition from Wiktionary, the free dictionary
Action noun of the verb הִתְלַהֵב (hitlahév), from the root ל־ה־ב (l-h-b). The “catching fire” sense is older, being attested since Medieval Hebrew, whereas the now-primary sense “enthusiasm” is attested only in Modern Hebrew.
- Enthusiasm: excitement, ado.
- (now uncommon) Catching fire: the event of igniting.
- (הִתְלַהֲבוּת־, hitlahavút-) Singular construct form of הִתְלַהֲבוּת.