Derogertory word used by the English and Australians for all American nationals. Derived from Rhyming slang (Septic Tank = Yank)
Will those stupid seppos ever shut up bragging about how much lemonade they can drink?
by William Balderdash March 17, 2003
An Australian slang term for an American. Seppo being short for Septic, which in turn being short for "Septic Tank"
"Did you hear how loud that seppo was on the train, what a dick"
by Aus John September 18, 2008
1. Seppo is an Australian term for Americans, derived from the Australian rhyme slang, "Septic Tank Yanks" due to their heightened sense of jealousy over America's modern toilet system. While still living in the dunny days of exterior outhouses, Australians envy the American septic tank systems that allow Americans to handle business in the comfort of their own home.
2. Seppo is an England and Australian term for Americans, who separated from the Olde Country to make a new life free from British culture. Seppo is an abbreviated form of separate or separatists.
"Some day when I visit America, I'm going to try out a Seppo Lou!"

Those Seppos leave our country, start a new country, and now they keep coming back! There's a Seppo everywhere you look!"
by Woweverynamereallyistaken March 25, 2019
A clueless bigot that has lost touch with reality. Derived from Sepp Blatter, the cluless bigot that has lost touch with reality
Unfortunately handshakes were not enough for the seppo to convine everyone else he wasn't a complete cunt.
by Ojay82 November 18, 2011
Slang for Americans - as septic tank rhymes with yank, but Americans are also full of shit like septic tanks
This seppo would not shut up about NFL last week
by Jun-YA October 10, 2006
Australian version of "American'. Comes from rhyming slang
Yank = septic tank = "seppo" in the shortened form. Common in Queensland!
We don't like seppos here!!
by Andrew Davison April 20, 2006
septic tank, rhyming slang for yank, an american person
would of been a good palace if it wasn't full of seppo wankers
by Anonymous December 9, 2002