Back in the '90s, the coolest people on the planet could be identified by their use of the word cowabunga. Preferably delivered in a foggy, just-baked, 4th-grade-reading-level fashion. For youngsters who have not yet unlocked the secrets of the past (again, the '90s), cowabunga was an exclamation of accord, happiness, or solidarity. For example:
You: "I just got an A on my math test."
Your half-baked friend: "Cowabunga, man!"
Your BFF: "Did you hear Jason Mark's parents are out of down and that he's having a rager?"
Your bro-friend: "Dude, I got her number and she said I could page her."
You: "Cowabunga, dude!"
Cowabunga has since faded from the American stoner vernacular, but you have to wonder...what did cowabunga mean, anyhow? Where did it come from?
The word is in fact a rather recent creation. It was writer of the Howdy Doody Show Eddie Kean who came up with the exclamation during his tenure on the show, which was between 1947 and 1954. For those who don't know, Howdy Doody was a western-themed children's TV show featuring a puppet named Howdy Doody. On the show was also a Native American character named Chief Thunderthud. Kean originally made up a greeting for this character — kawagoopa. (Kean couldn't use the more familiar "how" because he didn't want anything too closely resembling real Native Americans.) He then invented the term cowabunga for the Chief to use whenever he got mad or frustrated.
The kid-watchers of Howdy Doody became acquainted with cowabunga in the '50s. But in the '60s, the term somehow made its way into surfer culture as an exclamation of awesomeness related to catching waves, or as a greeting or goodbye. Its entrance into surf culture could be because its members were viewers of the Howdy Doody Show. Paul McFedries in his book, Weird Word Origins also points to the 1960s TV show Gidget as an influence: "...one of the characters would yell 'Cowabunga!' as he ran with his surfboard into the water."
Fast-forward to the '80s when all of a sudden, cowabunga was back, thanks to the Teenage Mutant Ninja Turtles and the character of Michelangelo, whose catch-phrase was cowabunga.
Bart Simpson also continued cowabunga's legacy in the '90s, however Bart's trademark phrase is largely due to a T-shirt that appeared with Bart skateboarding and the phrase. He actually rarely says it in the show.
So now you know. Cowabunga is not some term stemming from ancient Greek nor Latin nor any romance language. It was just a creation of a TV writer working in the '50s.