Evasion is the act of physically escaping from something, like your evasion of your ex-girlfriend at the prom — you kept dancing. Now that's fancy footwork.
Evasion also means "dodging something you are supposed to do" like your evasion of your chores by pretending to be sick. Evasion can also mean "the deliberate act of failing to pay money," like tax evasion, not paying your taxes. Though evasion comes from the Latin word evadere, "to escape," if you owe the government money, you'll surely be caught eventually.