Someone who is being a lamer in regards to the current conversation.
Like, if they say something stupid or confusing, you would look at them as if their hair is messed up.
Basically, a kid-friendly version of MoFo or mother f*cker.
Portmanteau of "modernist" and "afro", i.e. an afro hairstyle worn by modernist thinkers, or more loosely, early-20th century writers, such as poet Ezra Pound, playwright George S. Kaufman, The New Yorker founder Harold Ross, and playwright August Strindberg.
George S. Kaufman had some crazy jokes." "And some crazy hair. That guy had a mofro.