Mamona: Sucker (in the sense of a person who acts in a silly or childish way)
Weaned Calf: Actual meaning of the term, refers to a calf that has just been weaned
Pampered Child: Someone who is being overly protected or spoiled
Meaning
The word "mamona" has different meanings in Spanish depending on the context in which it is used. It can refer to a person who is being childish or acting in a silly manner. It can also refer to a calf that has just been weaned. In terms of frequency, "mamona" is not a very common term in Spanish and it is more likely to be used in oral speech than in written contexts.
Examples
¡Deja de ser tan mamona y ponte a trabajar!
Translation: Stop being so childish and get to work!
La mamona de la familia siempre quiere salirse con la suya.
Translation: The spoiled one in the family always wants to have her way.
Esa niña es una mamona, siempre quiere que la consientan.
Translation: That girl is a sucker, she always wants to be spoiled.
Idiomatic Expressions
Llorar como mamona: To cry excessively or over small matters
Ser mamón/mamona: To be annoying or needlessly demanding
Ponerse mamón/mamona: To act spoiled or childish
Examples of Idiomatic Expressions
Si sigues llorando como mamona, no te voy a prestar mis juguetes.
Translation: If you keep crying like a baby, I'm not going to lend you my toys.
No seas mamón, no todo puede ser como tú quieras.
Translation: Don't be a pain, not everything can be the way you want it.
Se pone mamona cada vez que no le dan lo que quiere.
Translation: She acts like a spoiled child every time she doesn't get what she wants.
Etymology
The term "mamona" comes from the word "mamón" which refers to a calf that has just been weaned from its mother's milk. In colloquial language, it is used to describe someone who is overly dependent or attached to something or someone.