Cotton headed ninny muggins is a compound insult from the 2003 Will Ferrell flick, “Elf”.
Cotton headed refers to the person in question having cotton in the place of their brains.
Ninny and muggins are both terms that are used for foolish, witless and dim people.
The phrase could be simply translated as empty headed idiot.
“Cotton headed ninny muggins” was coined by Will Ferrell in his 2003 Christmas movie about a man, who thinks he’s an elf, creatively titled “Elf”.
The film was premiered in the United States on October 9th, 2003 and it became a pop culture icon, thanks to its success among many.
It was first defined on Urban Dictionary in 2003, with several other entries having been written on the phrase since then.
“Cotton headed ninny muggings” became a popular phrase, closely associated with the movie, many fans watch to get into their festive mood.