ardor, ardour, elan, zeal (noun)

a feeling of strong eagerness (usually in favor of a person or cause)

"they were imbued with a revolutionary ardor"; "he felt a kind of religious zeal"

zeal (noun)

excessive fervor to do something or accomplish some end

"he had an absolute zeal for litigation"

readiness, eagerness, zeal, forwardness (noun)

prompt willingness

"readiness to continue discussions"; "they showed no eagerness to spread the gospel"; "they disliked his zeal in demonstrating his superiority"; "he tried to explain his forwardness in battle"

zeal (Noun)

The fervor or tireless devotion for a person, cause, or ideal and determination in its furtherance; diligent enthusiasm; powerful interest.