means Feeling or showing strong, intense emotion — especially eagerness, love, or conviction — about someone or something.

from From Latin 'passio,' suffering or enduring, itself from 'pati,' to suffer (the same root that gives us 'patient' and the Passion of Christ). The path runs through Late Latin 'passionatus' and Old French into Middle English. The original sense leaned hard on suffering — a 'passion' was something you underwent, an emotion that seized and pained you — and only later softened into the warmer modern flavor of ardor and zeal. The old logic survives in our sense that to be truly passionate is to be a little overtaken by your feelings rather than calmly in charge of them.