The Vietnamese word "vô hại" is an adjective that means "innocuous" or "harmless." It is used to describe something that does not cause any harm or danger.
Chất này là vô hại cho sức khỏe.
(This substance is harmless to health.)
Cô ấy chỉ nói đùa, những gì cô ấy nói là vô hại.
(She was just joking; what she said was innocuous.)