Melolengo
Someone who acts dumb. An idiot. Sometimes used by some Mexicans instead of calling their husband/wife/child/etc stupid / menso / pendejo in front of a crowd, it sounds nicer but means the same thing.
A: can you please get me my keys from the counter?
B: I don't see them.
A: *walks over* wow Melolengo, they're right in front of you!!
B: I don't see them.
A: *walks over* wow Melolengo, they're right in front of you!!