Malbebo is a humorous Esperanto word, meaning an elderly person. It comes from "bebo", the Esperanto word for "baby", with the prefix "mal-" added to signify "the opposite of". A literal English translation would be "unbaby".
Also, how do you report Danilo's response for being wrong? "Ugly" is an adjective, and adjectives can't end with "-o" in Esperanto. "-o" is for nouns, while "-a" is for adjectives. The word for "ugly" would be "malbela", literally meaning "un-beautiful".
Used in US as well
"La malbebo estas maljuna, cxar li havas 82 jaroj."