A phrase used to describe someone who is oblivious or unaware of something obvious, similar to the English phrase 'wearing your ignorance on your sleeve'. Literally translates to 'booger on the forehead'.
Examples
- Spanish: No se dio cuenta de que su novia estaba coqueteando con otro chico. Siempre tiene un moco en la frente.
- English: He didn't notice that his girlfriend was flirting with another guy. He always has a booger on his forehead.