Perhaps the most common use of contra is to mean "against" with the meaning of "in opposition to":
- La Unión Europea decidió imponer sanciones contra el presidente. (The European Union decided to impose sanctions against the president.)
- Se dedican a la lucha contra la explotación. (They are dedicated to the fight against exploitation.)
- Fue aprobada una medicina contra el cáncer en los EE.UU. (A medicine against cancer was approved in the U.S. An anti-cancer medicine was approved in the U.S.)
- ¡No más violencia contra las mujeres! (No more violence against women!)
- La opinión pública está contra la construcción de plantas nucleares. (Public opinion is against the construction of nuclear plants.)
- Todos están contra mí. (Everyone's against me.)
- La silla está contra la pared. (The chair is against the wall. The chair is next to the wall.)
- El biciclista chocó contra el árbol. (The bicyclist crashed against the tree. The bicyclist crashed into the tree.)
- La tiró contra la casa. (He threw it against the house. He threw it at the house.)
- Tengo cinco objeciones en contra de la ley. (I have five objections against the law.)
- Sobrevivió en contra de la adversidad. (She survived against the adversity.)
- Los trabajadores están en contra de nuevos horarios. (The workers are against the new schedules.)
- Su madre estaba en contra de que fuera cantante. (Her mother was against her being a singer.)
- Los profesores no están en contra de que Bush venga al país. (The teachers are not against Bush coming to the country.)
- El 61% están en contra de que el presidente vete la ley. (Sixty-one percent are against the president vetoing the law.)

