slang Extremely large in size, amount, scale, or degree. That joke got some mondo laughs from the audience. Whoa, dude, this is, like, a mondo house your parents own. You'll need to throw down some mondo bucks to afford going there, but it really is the best vacation I've ever taken.

slang Extremely bizarre, strange, unusual. Hyphenated if used before a noun. It's just mondo bizarro to think that this sheep is an actual genetic clone of another one! I love having the audience make suggestions for our improv group—you always get some mondo-bizarro scenarios from it!