The other day I was talking to someone who is learning Spanish, and she said, amid an expression, "en favor o a contra", instead of "a favor o en contra". After correcting her, she asked me why the custom of using "a" and "en" in one way and not the other, and why not using the same in both. I could not reply.

I have had a hard time finding explanations for this. Google has not yield anything satisfactory. Any of you have any idea?

Obviously, "en contra" sound better than "a contra", because we are used to it. However, expressions like "a contracorriente" might indicate that "a contra" is actually reasonable.

Likewise, "a favor" sound better than "en favor", but I see no a priori reason why the latter is grammatically incorrect.


2 Answers 2


"En contra" is an adverbial phrase

En contra es una locución adverbial que significa ‘en oposición a’: [...]

Con verbos que significan oponerse a algo o a alguien, se pueden emplear la preposición contra o la locución adverbial en contra de:

Both a and en have spatial "usage" as prepositions. Not only "en favor" is valid, but we also say "(ir) a contracorriente", "por contra" (meaning "por el contrario"). I believe that "en contra" is a shortened form of "en contraposición a".

My guess is that since these particular prepositions explain not only "direction" (Voy a Madrid - meaning "hacia", towards) or "situation" (está a tu izquierda; está en la mesa) but also "mode" (Tú vas a pie, yo voy en barco) we use 'en' to reflect that we (figuratively rather than physically) stand against it (the other idea, suggestion, etc.). Let's compare

  • Entró a su casa

  • Entró en su casa

Both carry the same meaning, but (the subtle) connotations could be for the first one more stress in the action ("ir hacia dentro") and for the second the situation or final outcome (llegar físicamente dentro).

Again, for

Tú vas a pie, yo voy en barco

I'm inside the boat, you move towards your destination.

Thus, we can say "a favor" and "en favor": I "flow" with your action or idea for the first one and I "stand" -meaning support. For contra, the adverbial phrase "en contra" would be a figuratively position against something. But this might be a far shot.


Prepositions just are. I learned that from English Language & Usage. You can help your friend learn patterns, to help her remember which preposition to use in certain situations, and you can reassure her that prepositions will probably be her last frontier in her language learning odyssey. That's about it, though.

  • @walen - That was my best effort, and I cited my source. I look forward to reading better answers. Feb 14, 2018 at 16:39
  • you can still explain why they "just are" or when they started "just being". I agree with Walen.
    – Brian H.
    Feb 14, 2018 at 16:43
  • @BrianH. - Saying that they just are means there is no explanation (in my opinion); the question did not ask for etymology. Feb 14, 2018 at 19:36
  • 1
    Aparente: I agree on your statement that prepositions just are. However, as is now, this is more a comment than an answer. Consider editing to include some relevant info or just moving it into comments.
    – fedorqui
    Feb 15, 2018 at 13:03

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