Someone who does or says really random, stupid things. Usually a tardicus will do those stupid things on a daily basis as if it were some type of habit or hobby. Also, a tardicus' absurd behavior will interupt your day. This word is taken from the word " 'tard" which comes from the word "retard" meaning "to slow down" (The -cus is just to add insult to injury and flair to the term).
victim#34:"Did you see that woman skipping through the food court singing the theme to "Hannah Montana"?
victim#35:"Yeah! she's really slowing my day down! SHE'S SUCH A TARDICUS!"