Chile is known for its countless chilenismos or slang words and phrases.
“Ojo” in Spanish means eye. However, when used in proper context “ojo” takes on another meaning in Chile.
If you tell someone “ojo” in Chile, it means that they should be careful. Implying that they should watch their back, look out for someone or something that may do them harm.
Saying the phrase “ojo” can be accompanied with the speaker pointing to his or her eye.
So if someone says “ojo” to you, be careful.