Strong's 2205 (ζῆλος)

emulation, envy(-ing), fervent mind, indignation, jealousy, zeal

properly, heat, i.e. (figuratively) "zeal" (in a favorable sense, ardor; in an unfavorable one, jealousy, as of a husband (figuratively, of God), or an enemy, malice)

from G2204 (ζέω);