say it: in-THOO-zee-az-uhm
enthusiasm is a noun meaning "a feeling of excitement". It carries 3 recorded senses.
a feeling of excitement
overflowing with eager enjoyment or approval
a lively interest
“enthusiasm for his program is growing”
Forms marked · are formed by the regular rule rather than recorded in the source data. English keeps a few hundred irregulars and the rest follow the pattern, so the rule is right far more often than not — but it is a rule, and the mark says so.
Definitions, synonyms and semantic relations for enthusiasm come from Princeton University’s WordNet. The pronunciation comes from the CMU Pronouncing Dictionary. Commonness is measured against a corpus of everyday English. Full sources and licences.