Think of how 'association' is spelled. There's an S-O-C in there, association, and people shortened that word into soccer. So instead of saying association you'd just say soccer.

想一想“association” 是如何拼写的。 那里有一个 S-O-C，协会，人们将该词缩写为足球。 所以与其说协会， 不如说足球。