¡La Esquina de la Gramática! Rule 10

Prefixes in Spanish… hyphen or not?

It depends…

Prefixes are affix elements that lack autonomy, and they are placed before a lexical base. Below are the rules to follow when you use them in Spanish.

- They always go right next to the base word when the base word is universal (only one word):

Exjefe, exnovio, exministro, provida, vicesecretario, superaburrido, etc.

Then, it would be incorrect to use a hyphen or leave a space in the following cases:

Anti-mafia or anti mafia

Anti-cancerígeno or anti cancerígeno

- If there are several prefixes, same thing, you don't leave any spaces or a hyphen in between:

Antiposmodernista, requetesuperguapo

- The only two instances when we need to use a hyphen are: 1) When the base word starts with a capital letter, for example: anti-ALCA, mini-USB, pro-Obama. That way you don’t have a lower case right next to a capital letter case. 2) When the base word is a number: sub-21.

- Also, when the base word is made of several words (multi-verbal), you need to leave a space after the prefix:

Ex relaciones públicas

Anti pena de muerte

Source: http://www.rae.es