German phrase
Ich bin dagegen.
Meaning
I'm against it
When to use it
It means you oppose something. It is common in conversation and can sound strong when emotional.
Example dialogue
Wir lassen die Sicherheitskontrolle dieses Mal weg.
We're skipping the safety check this time.
Ich bin dagegen. Sicherheit geht vor.
I'm against it. Safety comes first.