no tener dos dedos de frente

== Spanish == === Etymology === Literally, “not to have a two finger forehead”. "Dos dedos" (Two fingers) is an unofficial measuring unit, roughly 3 to 4 cm measuring one finger on top of the other, and it is used to mean that someone is not very smart, as shown by displaying a forehead that only measures 3 to 4 cm high(two fingers). === Verb === no tener dos dedos de frente (first-person singular present no tengo dos dedos de frente, first-person singular preterite no tuve dos dedos de frente, past participle no tenido dos dedos de frente) (idiomatic) to be an idiot, to be thick as a plank === Further reading === “no tener dos dedos de frente”, in Diccionario de la lengua española [Dictionary of the Spanish Language] (in Spanish), online version 23.8.1, Royal Spanish Academy [Spanish: Real Academia Española], 15 December 2025