I went to the store yesterday, here's the kicker, I saw Mr. Dirks, my math teacher! One side has the word, one side has the definition. Definition of kicker in the galva108.de dictionary. Information and translations of kicker in the most comprehensive dictionary definitions resource on the web. A kicker is, at the most basic level, one that kicks. Unsurprisingly, it's used mostly in sports contexts. It can also mean, in American informal English, “an.