against [əˈɡenst]
When against is an element in a phrasal verb, eg go against, run up against, look up the verb.
preposición
1 (in opposition to) [+person] contra; en contra de; [+plan] en contra de
what have you got against me? ¿qué tiene usted en contra de mí?; ¿qué tiene usted contra mí?; I spoke against the plan hablé en contra del proyecto; I see nothing against it no veo nada en contra; he was against it estaba en contra; se opuso a ello; he was against going estaba en contra de ir; it's against the law la ley lo prohíbe; es ilegal; it's against the rules no lo permiten las reglas; conditions are against us las condiciones nos son desfavorables; luck was against him la suerte le era contraria
to stand or run against sb (Pol) presentarse en contra de algn
to be up against it estar en un aprieto
now we're really up against it! ¡ahora sí tenemos problemas!
2 (in contact with) contra
he hit his head against the wall se dio con la cabeza contra la pared; he leant the ladder against the wall apoyó la escalera contra la pared
3 (in front of) contra
against the light contra la luz; a contrasol; the hills stood out against the sunset las colinas se destacaban sobre la puesta del sol