Conceivably derived from "exactamente," Spanish for "exactly."

It is used primarily by U.S. non-Spanish speakers. The Fonz, a hip irreverent character on the 50s TV show The Happy Days is responsible for some of the earliest recorded utterances though it's likely to have been in use before then.

The second half of the world "mundo," possibly results from mishearing exactamente and, in another context, mundo, "world" in Spanish. Interestingly the understood meaning has nothing to do with the meaning "world." Even so in Spanish it might translate as "exact world," though the gender of "exacta" renders the phrase grammatically correct.
Pinky: I see, so tonight you want to take over the world.
Brain: Exactamundo.
by earl of grey May 5, 2011
Get the Exactamundo mug.
Exactamundo is the way English people pronounce the Spanish word Exactamente, that means: Exactly...
- Are you leaving?
- Exactamundo
by martin martin May 1, 2009
Get the Exactamundo mug.
Meaning 'exactly' or 'precisely'. It is a variation of 'exactly' just with additional syllables for improved pronounciation.
- "So you get a free ride AND free money? That's great!..."
- "Exactamundo! That's what I thought"
by Josh Bertram Martin June 22, 2007
Get the Exactamundo mug.
Means 'yes,' 'exactly,' 'right,' or 'that's correct.' The word appears to be derived from the English word 'exactly.'
"So, you're taking Heather out to the dance?"
by Stephanie M. October 27, 2003
Get the exactamundo mug.