"Mocoso" is a noun, but it can also be used as an adjective in colloquial contexts.
/moˈko.so/
In Spanish, "mocoso" typically refers to a child, often in a derogatory sense, suggesting that the child is spoiled, bratty, or immature. The term can also relate to someone who behaves in a childish or irresponsible manner. It is more frequently used in oral speech rather than written contexts, as it carries a colloquial tone that conveys familiarity or disdain.
Ese mocoso no deja de hacer travesuras.
That brat won’t stop causing trouble.
No seas mocoso y acepta la derrota.
Don’t be a brat and accept defeat.
El mocoso se cree el rey de la casa.
The kid thinks he’s the king of the house.
The term "mocoso" is often used in idiomatic expressions in Spanish, usually conveying a sense of immaturity or mischief.
Siempre hace lo que quiere, ese es un mocoso consentido.
He always does what he wants; he is a spoiled kid.
No hables con ese mocoso, solo sabe dar problemas.
Don’t talk to that brat; he only knows how to cause trouble.
Esa actitud de mocoso no te llevará a ninguna parte.
That bratty attitude won’t get you anywhere.
Me parece que ese mocoso no ha aprendido a respetar a los mayores.
I think that kid hasn’t learned to respect adults.
Cuando se comporta así, parece un mocoso sin educación.
When he behaves like that, he seems like a kid without manners.
The word "mocoso" likely derives from "mocos", which means "snot" in Spanish. The connection emphasizes the immature and often untidy image associated with little children, who are prone to runny noses and childish behavior.
Overall, "mocoso" is a common term in colloquial Spanish, reflecting both linguistic playfulness and cultural attitudes towards childhood and immaturity.